Merge branch 'develop' into serialHal

* fix: right-size warm tier for constrained platforms and feed RP2040 watchdog during NodeDB save

* fix: size warm tier and traffic cache per-MCU RAM, lowering no-PSRAM ESP32 (classic/S2/C3) tiers

* docs: document nRF52/RP2040 #else fall-through in warm tier and TM cache cascades

.claude/settings.json

@@ -0,0 +1,17 @@
+{
+  "hooks": {
+    "PostToolUse": [
+      {
+        "matcher": "Write|Edit",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "f=$(tr -d '\\n' | grep -o '\"file_path\"[[:space:]]*:[[:space:]]*\"[^\"]*\"' | head -1 | sed 's/.*:[[:space:]]*\"//; s/\"$//'); [ -n \"$f\" ] && [ -f \"$f\" ] || exit 0; t=$(command -v trunk || echo \"$HOME/.cache/trunk/launcher/trunk\"); [ -x \"$t\" ] || { echo \"trunk-fmt hook: trunk not found; its launcher needs curl or wget to bootstrap the CLI (see 'Formatting & the trunk toolchain' in .github/copilot-instructions.md)\" >&2; exit 1; }; out=$(\"$t\" fmt --force \"$f\" 2>&1) || { echo \"trunk-fmt hook: trunk fmt failed on $f: $out\" >&2; exit 1; }",
+            "timeout": 120,
+            "statusMessage": "Formatting (trunk)..."
+          }
+        ]
+      }
+    ]
+  }
+}

.github/copilot-instructions.md

@@ -191,7 +191,24 @@ Writers go through `setNodeStatus`, `updatePosition`, `updateTelemetry` (which d
 
 ### Eviction
 
-Every code path that drops a node from the header table must also evict the satellites. The single chokepoint is `eraseNodeSatellites(NodeNum)`; it's already called from `getOrCreateMeshNode`'s oldest-boring eviction, `removeNodeByNum`, both branches of `resetNodes`, `cleanupMeshDB`, `addFromContact`'s ignored-branch, and `AdminModule`'s `set_ignored_node`. Add new eviction sites here, not by calling `.erase()` directly.
+Every code path that drops a node from the header table must also evict the satellites. The single chokepoint is `eraseNodeSatellites(NodeNum)`; it's already called from `getOrCreateMeshNode`'s oldest-boring eviction, `demoteOldestHotNodesToWarm` (the over-cap warm-tier migration), `removeNodeByNum`, both branches of `resetNodes`, `cleanupMeshDB`, `addFromContact`'s ignored-branch, and `AdminModule`'s `set_ignored_node`. Add new eviction sites here, not by calling `.erase()` directly. (Note: `enforceSatelliteCaps`/`evictSatelliteOverCap` call `.erase()` directly on purpose — that's a satellite-only cap trim where the node _stays_ in the header, a different operation from this chokepoint.)
+
+### Warm tier (long-tail identity)
+
+On every arch except STM32WL and bare nRF52832 (`WARM_NODE_COUNT > 0`), a node evicted from the header table is not forgotten outright: `WarmNodeStore` (`src/mesh/WarmNodeStore.{h,cpp}`) keeps a 40 B `{num, last_heard, public_key}` record per evicted node — primarily so PKI DMs to/from a long-tail node keep decrypting without re-running a NodeInfo exchange (the rest of `NodeInfoLite` rebuilds from traffic in seconds).
+
+- **Write:** `getOrCreateMeshNode`'s eviction and `demoteOldestHotNodesToWarm` (the over-cap boot migration) call `warmStore.absorb(num, last_heard, key)` _before_ the node leaves the header.
+- **Read-back:** `getOrCreateMeshNode` calls `warmStore.take()` to rehydrate `last_heard` + key when a warm node is re-admitted; `copyPublicKey()` falls back to the warm tier so the PKI send path finds keys for evicted peers.
+- **Persistence:** nRF52840 uses a 12 KB raw-flash record-ring at `0xEA000` (below LittleFS; append + replay + compact-on-rotate, link-guarded by `nrf52840_s140_v7.ld` and `extra_scripts/nrf52_warm_region.py`). Everywhere else: a `/prefs/warm.dat` snapshot flushed by `saveIfDirty()` on the node-DB save cadence.
+- **Tunables** (`mesh-pb-constants.h`): `WARM_NODE_COUNT` (per-arch; `0` disables the tier) and `MAX_NUM_NODES` (hot cap — 120 on nRF52840/generic ESP32 to fit the 28 KB LittleFS; ESP32-S3 keeps its flash-scaled 100/200/250, portduino 250). Verbose migration/self-care tracing routes through `LOG_MIGRATION`, gated by `MESHTASTIC_NODEDB_MIGRATION_VERBOSE`.
+
+### Satellite caps
+
+Only the freshest `MAX_SATELLITE_NODES` nodes keep satellite payloads; the rest of the header table carries just the `NodeInfoLite`. The cap is **per-platform**: 40 on RAM-constrained parts (nRF52840, generic ESP32) since the four maps live in internal SRAM (not PSRAM, ~408 B/node across the four), and 250 on flash-rich hosts (ESP32-S3, portduino) so every hot node can carry rich data as before the cap existed. `enforceSatelliteCaps()` trims each map to the cap on load (returns whether it trimmed); `evictSatelliteOverCap()` trims before each insert. Eviction is by the owning node's hot `last_heard` (stalest first, demoted/absent nodes rank as `last_heard==0`); self is never trimmed.
+
+### On-boot self-care
+
+`NodeDB::nodeDBSelfCare()` runs once identity is established (the constructor after key (re)gen, and `reloadFromDisk()` — _not_ inside `loadFromDisk`, where `getNodeNum()` is still 0). It confirms self is present (warns if a non-empty DB is missing us — a foreign/over-cap file), pins self to index 0, demotes/trims only **non-self** overflow into the warm tier, then rewrites `nodes.proto` **once** and only if it healed something — and never while encrypted storage is locked (it would persist placeholder defaults). `loadFromDisk` deliberately leaves the loaded store untrimmed for this pass.
 
 ### Sync flow: thin NodeInfo + post-COMPLETE_ID replay (no opt-in)
 
@@ -283,6 +300,15 @@ firmware/
 
 ## Coding Conventions
 
+### Formatting & the trunk toolchain
+
+`trunk fmt` is the project formatter (`trunk_check` CI rejects unformatted code). For Claude Code users, `.claude/settings.json` ships a PostToolUse hook that runs `trunk fmt --force` on every file the agent writes or edits. The hook is pure sh/grep/sed — no python or jq required — but trunk itself must be able to run:
+
+- Trunk's launcher (`~/.cache/trunk/launcher/trunk`, or `trunk` on PATH) downloads the CLI version pinned in `.trunk/trunk.yaml` on first use and again whenever that pin is bumped. **The launcher needs `curl` or `wget`**; without one it fails with "Cannot download… please install curl or wget", and the hook surfaces that as a warning on every write.
+- No curl/wget available (e.g. a minimal WSL image)? Bootstrap by hand with any Python (PlatformIO bundles one at `~/.platformio/penv/bin/python`): download `https://trunk.io/releases/<ver>/trunk-<ver>-linux-x86_64.tar.gz` and place the `trunk` binary at `~/.cache/trunk/cli/<ver>-linux-x86_64/trunk` (chmod +x), where `<ver>` is the `cli.version` from `.trunk/trunk.yaml`.
+- The hook fails loudly by design (visible warning, non-blocking). Silent no-op formatting hooks hide real breakage — don't re-add `2>/dev/null || true` around the whole thing.
+- More generally: don't assume a stock Linux userland in hooks or helper scripts — minimal WSL/container images may lack `python3`, `curl`, `wget`, and `jq`. Prefer plain sh + coreutils, or PlatformIO's bundled Python for anything heavier.
+
 ### General Style
 
 - Follow existing code style - run `trunk fmt` before commits

.github/workflows/flasher-link-comment.yml

@@ -0,0 +1,187 @@
+name: Post Web Flasher Link Comment
+
+on:
+  workflow_run:
+    workflows: [CI]
+    types: [completed]
+
+permissions:
+  pull-requests: write
+  actions: read
+
+jobs:
+  post-flasher-link:
+    if: >
+      github.event.workflow_run.event == 'pull_request' &&
+      github.event.workflow_run.conclusion != 'cancelled' &&
+      github.repository == 'meshtastic/firmware'
+    continue-on-error: true
+    runs-on: ubuntu-latest
+    steps:
+      # Per-board manifests carry the firmware's own metadata (activelySupported,
+      # displayName, ...) generated from each target's custom_meshtastic_* config.
+      - name: Download board manifests
+        uses: actions/download-artifact@v8
+        continue-on-error: true
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          run-id: ${{ github.event.workflow_run.id }}
+          pattern: manifest-*
+          path: ./manifests
+          merge-multiple: true
+
+      - name: Post or update web flasher link comment
+        uses: actions/github-script@v8
+        with:
+          script: |
+            const marker = '<!-- web-flasher-link -->';
+            const run = context.payload.workflow_run;
+            const { owner, repo } = context.repo;
+
+            // Resolve the PR by matching the run's head SHA against the repo's open
+            // PRs. workflow_run.pull_requests is empty for fork PRs, and
+            // listPullRequestsAssociatedWithCommit won't return an open fork PR by
+            // its head commit — but pulls.list includes fork PRs. Matching on head
+            // SHA also enforces that the run is for the PR's current commit, so stale
+            // re-runs of an outdated commit won't match.
+            const openPrs = await github.paginate(github.rest.pulls.list, {
+              owner, repo, state: 'open', per_page: 100,
+            });
+            const pr = openPrs.find((p) => p.head.sha === run.head_sha);
+            if (!pr) {
+              core.info(`No open pull request matches commit ${run.head_sha}; skipping.`);
+              return;
+            }
+            const prNumber = pr.number;
+
+            // Restrict to trusted authors. NOTE: author_association is computed for
+            // the GITHUB_TOKEN, which cannot see *private/concealed* org memberships —
+            // those members come back as CONTRIBUTOR, not MEMBER. So gating on MEMBER
+            // alone silently excludes most maintainers. We allow the trusted set the
+            // token can actually identify (members, collaborators, and anyone with a
+            // previously merged PR). For strict members-only you'd need an org-read
+            // App/PAT token to call orgs.checkMembershipForUser.
+            const allowedAssociations = ['OWNER', 'MEMBER', 'COLLABORATOR', 'CONTRIBUTOR'];
+            if (!allowedAssociations.includes(pr.author_association)) {
+              core.info(`Author association ${pr.author_association} is not trusted; skipping.`);
+              return;
+            }
+
+            // Require at least one per-arch firmware artifact from gather-artifacts
+            const artifacts = await github.paginate(github.rest.actions.listWorkflowRunArtifacts, {
+              owner, repo, run_id: run.id, per_page: 100,
+            });
+            const archRe = /^firmware-(esp32|esp32s3|esp32c3|esp32c6|nrf52840|rp2040|rp2350|stm32)-(\d+\.\d+\.\d+\.[0-9a-f]+)$/;
+            const archArtifacts = artifacts.filter((a) => archRe.test(a.name) && !a.expired);
+            if (archArtifacts.length === 0) {
+              core.info('No per-arch firmware artifacts found; skipping.');
+              return;
+            }
+
+            const version = archRe.exec(archArtifacts[0].name)[2];
+            const expiresAt = archArtifacts[0].expires_at
+              ? new Date(archArtifacts[0].expires_at).toISOString().slice(0, 10)
+              : null;
+
+            // Read each built board's manifest (.mt.json). activelySupported,
+            // displayName and architecture come straight from the board's
+            // custom_meshtastic_* platformio config, so the list is in sync with
+            // the firmware itself — no external device database needed.
+            const fs = require('fs');
+            let boards = [];
+            try {
+              boards = fs.readdirSync('./manifests')
+                .filter((f) => f.endsWith('.mt.json'))
+                .map((f) => {
+                  try { return JSON.parse(fs.readFileSync(`./manifests/${f}`, 'utf8')); }
+                  catch { return null; }
+                })
+                .filter((m) => m && m.activelySupported === true && m.platformioTarget)
+                .map((m) => ({
+                  board: m.platformioTarget,
+                  platform: m.architecture || '',
+                  // displayName is maintainer-authored text; escape table-breaking pipes
+                  displayName: String(m.displayName || m.platformioTarget).replace(/\|/g, '\\|'),
+                  image: Array.isArray(m.images) && m.images[0] ? String(m.images[0]) : '',
+                }))
+                .sort((a, b) => a.board.localeCompare(b.board));
+            } catch (e) {
+              core.warning(`Could not read board manifests: ${e.message}`);
+            }
+
+            const flasherUrl = `https://flasher.meshtastic.org/?pr=${prNumber}`;
+            // Device illustrations are served by the flasher from the same image
+            // names the manifest declares (custom_meshtastic_images). The flasher
+            // serves its SPA shell (HTML, 200) for unknown paths, so confirm each
+            // image really resolves to an image before linking it.
+            const imageBase = 'https://flasher.meshtastic.org/img/devices/';
+            await Promise.all(boards.map(async (b) => {
+              if (!b.image) return;
+              try {
+                const res = await fetch(`${imageBase}${encodeURIComponent(b.image)}`);
+                const type = res.headers.get('content-type') || '';
+                if (!res.ok || !type.startsWith('image/')) b.image = '';
+              } catch { b.image = ''; }
+            }));
+
+            const boardLines = boards
+              .map((b) => {
+                const img = b.image ? `<img src="${imageBase}${encodeURIComponent(b.image)}" alt="" height="34">` : '';
+                return `| ${img} | ${b.displayName} | [\`${b.board}\`](${flasherUrl}&device=${encodeURIComponent(b.board)}) | ${b.platform} |`;
+              })
+              .join('\n');
+
+            // Shields.io badges. Only non-user-controlled, charset-constrained values
+            // (version, commit sha, counts, dates) go into badge URLs — never board
+            // names or the PR title — so the rendered comment cannot be spoofed.
+            const shieldText = (s) =>
+              encodeURIComponent(String(s).replace(/-/g, '--').replace(/_/g, '__').replace(/ /g, '_'));
+            const shield = (label, message, color) =>
+              `https://img.shields.io/badge/${shieldText(label)}-${shieldText(message)}-${color}`;
+            const buttonUrl =
+              `https://img.shields.io/badge/${shieldText('Flash this PR in the Web Flasher')}-2C2D3C?style=for-the-badge`;
+            const badges = [
+              `![firmware](${shield('firmware', version, '67EA94')})`,
+              `![commit](${shield('commit', run.head_sha.slice(0, 7), '2C2D3C')})`,
+              `![boards](${shield('boards', boards.length, '5C6BC0')})`,
+            ];
+            if (expiresAt) badges.push(`![expires](${shield('expires', expiresAt, '9A4E00')})`);
+
+            // Only render the board table when there are supported boards to list
+            const boardTable = boards.length > 0 ? [
+              `<details><summary>Supported boards built by this PR (${boards.length})</summary>`,
+              '',
+              '| | Device | Board | Platform |',
+              '| --- | --- | --- | --- |',
+              boardLines,
+              '',
+              '</details>',
+              '',
+            ] : [];
+
+            const body = [
+              marker,
+              '## ⚡ Try this PR in the Web Flasher',
+              '',
+              `[![Flash this PR in the Web Flasher](${buttonUrl})](${flasherUrl})`,
+              '',
+              badges.join(' '),
+              '',
+              '> [!WARNING]',
+              '> This is an automated, unreviewed CI test build. Back up your device configuration',
+              '> before flashing, and only flash devices you are able to recover.',
+              '',
+              ...boardTable,
+              `*Build artifacts expire${expiresAt ? ` on ${expiresAt}` : ' after 30 days'}. Updated for \`${run.head_sha.slice(0, 7)}\`.*`,
+            ].join('\n');
+
+            // Sticky comment: update in place when the marker is found
+            const comments = await github.paginate(github.rest.issues.listComments, {
+              owner, repo, issue_number: prNumber, per_page: 100,
+            });
+            const existing = comments.find((c) => c.body?.includes(marker));
+            if (existing) {
+              await github.rest.issues.updateComment({ owner, repo, comment_id: existing.id, body });
+            } else {
+              await github.rest.issues.createComment({ owner, repo, issue_number: prNumber, body });
+            }

.github/workflows/flasher-link-placeholder.yml

@@ -0,0 +1,62 @@
+name: Post Web Flasher Build Placeholder
+
+# Drops an immediate "build in progress" comment when a PR opens, so the web
+# flasher entry shows up right away. The real CI-driven workflow
+# (flasher-link-comment.yml) later replaces it in place via the shared marker.
+#
+# SECURITY: this uses pull_request_target (write token, runs for fork PRs) but is
+# safe because it never checks out or runs PR code and posts a fully static body
+# — no PR title, branch name, or other untrusted input is used anywhere.
+
+on:
+  pull_request_target:
+    types: [opened, reopened]
+
+permissions:
+  pull-requests: write
+
+jobs:
+  post-placeholder:
+    if: github.repository == 'meshtastic/firmware'
+    continue-on-error: true
+    runs-on: ubuntu-latest
+    steps:
+      - name: Post web flasher build-in-progress placeholder
+        uses: actions/github-script@v8
+        with:
+          script: |
+            const marker = '<!-- web-flasher-link -->';
+            const { owner, repo } = context.repo;
+            const pr = context.payload.pull_request;
+
+            // Trusted authors only (matches the real workflow). author_association
+            // can't reflect private org membership for the token, so concealed
+            // members appear as CONTRIBUTOR — include it, or maintainers are excluded.
+            const allowedAssociations = ['OWNER', 'MEMBER', 'COLLABORATOR', 'CONTRIBUTOR'];
+            if (!allowedAssociations.includes(pr.author_association)) {
+              core.info(`Author association ${pr.author_association} is not trusted; skipping.`);
+              return;
+            }
+
+            // Only seed a placeholder when no flasher comment exists yet — never
+            // overwrite a real (or existing placeholder) comment.
+            const comments = await github.paginate(github.rest.issues.listComments, {
+              owner, repo, issue_number: pr.number, per_page: 100,
+            });
+            if (comments.some((c) => c.body?.includes(marker))) {
+              core.info('Flasher comment already exists; nothing to do.');
+              return;
+            }
+
+            const body = [
+              marker,
+              '## ⚡ Try this PR in the Web Flasher',
+              '',
+              '> [!NOTE]',
+              '> Building this pull request… the flash button, badges and supported-board',
+              '> list will appear here automatically once CI finishes.',
+            ].join('\n');
+
+            await github.rest.issues.createComment({
+              owner, repo, issue_number: pr.number, body,
+            });

.github/workflows/main_matrix.yml

@@ -82,8 +82,9 @@ jobs:
       fail-fast: false
       matrix:
         check: ${{ fromJson(needs.setup.outputs.check) }}
-    # Use 'arctastic' self-hosted runner pool when checking in the main repo
-    runs-on: ${{ github.repository_owner == 'meshtastic' && 'arctastic' || 'ubuntu-latest' }}
+    # Runs on GitHub-hosted runners so checks don't compete with builds for the
+    # self-hosted 'arctastic' pool (which builds use).
+    runs-on: ubuntu-latest
     if: ${{ github.event_name != 'workflow_dispatch' && github.repository == 'meshtastic/firmware' }}
     steps:
       - uses: actions/checkout@v6
@@ -286,11 +287,11 @@ jobs:
             --limit 1 --json databaseId --jq '.[0].databaseId // empty')
           if [ -n "$RUN_ID" ]; then
             ARTIFACT_NAME=$(gh api "repos/${{ github.repository }}/actions/runs/${RUN_ID}/artifacts" \
-              --jq '.artifacts[] | select(.name | startswith("firmware-sizes-")) | .name' | head -1)
+              --jq '.artifacts[] | select(.name | startswith("firmware-sizes-")) | select(.expired == false) | .name' | head -1)
             if [ -n "$ARTIFACT_NAME" ]; then
               gh run download "$RUN_ID" -R "${{ github.repository }}" \
                 --name "$ARTIFACT_NAME" --dir ./baseline-develop/
-              cp "./baseline-develop/${ARTIFACT_NAME}/current-sizes.json" ./develop-sizes.json
+              cp "./baseline-develop/current-sizes.json" ./develop-sizes.json
               echo "found=true" >> "$GITHUB_OUTPUT"
             else
               echo "found=false" >> "$GITHUB_OUTPUT"
@@ -311,11 +312,11 @@ jobs:
             --limit 1 --json databaseId --jq '.[0].databaseId // empty')
           if [ -n "$RUN_ID" ]; then
             ARTIFACT_NAME=$(gh api "repos/${{ github.repository }}/actions/runs/${RUN_ID}/artifacts" \
-              --jq '.artifacts[] | select(.name | startswith("firmware-sizes-")) | .name' | head -1)
+              --jq '.artifacts[] | select(.name | startswith("firmware-sizes-")) | select(.expired == false) | .name' | head -1)
             if [ -n "$ARTIFACT_NAME" ]; then
               gh run download "$RUN_ID" -R "${{ github.repository }}" \
                 --name "$ARTIFACT_NAME" --dir ./baseline-master/
-              cp "./baseline-master/${ARTIFACT_NAME}/current-sizes.json" ./master-sizes.json
+              cp "./baseline-master/current-sizes.json" ./master-sizes.json
               echo "found=true" >> "$GITHUB_OUTPUT"
             else
               echo "found=false" >> "$GITHUB_OUTPUT"

.github/workflows/test_native.yml

@@ -37,13 +37,33 @@ jobs:
           sed -i -e "s#${PWD}#.#" coverage_base.info # Make paths relative.
 
       - name: Integration test
+        # Cap the whole step: if the simulator ever fails to exit (e.g. the
+        # exit_simulator admin path regresses again) the job must fail fast,
+        # not run to GitHub's 6-hour limit.
+        timeout-minutes: 5
         run: |
           .pio/build/coverage/meshtasticd -s &
           PID=$!
+          trap 'kill "$PID" 2>/dev/null || true' EXIT
           timeout 20 bash -c "until ls -al /proc/$PID/fd | grep socket; do sleep 1; done"
           echo "Simulator started, launching python test..."
           python3 -c 'from meshtastic.test import testSimulator; testSimulator()'
-          wait
+          # The Python harness sends exit_simulator and exits; the simulator is
+          # expected to terminate on its own. Give it a moment, then verify.
+          # If it is still alive the exit handshake is broken — fail loudly and
+          # do NOT fall through to `wait`, which would otherwise block until the
+          # job's hard timeout.
+          for i in $(seq 1 10); do
+            kill -0 "$PID" 2>/dev/null || break
+            sleep 1
+          done
+          if kill -0 "$PID" 2>/dev/null; then
+            echo "::error title=Simulator did not exit::meshtasticd ignored exit_simulator and is still running after the integration test. The exit_simulator admin path is broken (see AdminModule::handleReceivedProtobuf, ARCH_PORTDUINO bypass). Killing it to avoid a 6-hour CI overrun."
+            kill -9 "$PID" 2>/dev/null || true
+            wait "$PID" 2>/dev/null || true
+            exit 1
+          fi
+          wait "$PID" 2>/dev/null || true
 
       - name: Capture coverage information
         if: always() # run this step even if previous step failed
@@ -141,6 +161,14 @@ jobs:
           name: platformio-test-report-${{ steps.version.outputs.long }}
           merge-multiple: true
 
+      - name: Drop no-status testsuites from the report
+        # PlatformIO emits a self-closing <testsuite tests="0"/> row for every test_* dir
+        # crossed with every hardware variant it cannot run on the native host (~4900 rows).
+        # They carry no pass/fail/skip status and bury the suites that actually ran. Strip
+        # them so the Test Report lists only suites with a real status. Only the copy the
+        # reporter renders is trimmed; the uploaded artifact keeps the full XML.
+        run: sed -i -E 's#<testsuite [^>]*tests="0"[^>]*/>##g' testreport.xml
+
       - name: Test Report
         uses: dorny/test-reporter@v3.0.0
         with:

.github/workflows/update_protobufs.yml

@@ -16,13 +16,18 @@ jobs:
           submodules: true
 
       - name: Update submodule
-        if: ${{ github.ref == 'refs/heads/master' || github.ref == 'refs/heads/develop' }}
+        if: ${{ github.ref_name == 'master' || github.ref_name == 'develop' }}
+        working-directory: protobufs
+        env:
+          # Use the branch that triggered the workflow as the protobuf branch.
+          GIT_BRANCH: ${{ github.ref_name }}
         run: |
-          git submodule update --remote protobufs
+          git fetch --prune origin $GIT_BRANCH
+          git checkout origin/$GIT_BRANCH
 
       - name: Download nanopb
         run: |
-          wget https://jpa.kapsi.fi/nanopb/download/nanopb-0.4.9.1-linux-x86.tar.gz
+          wget https://github.com/nanopb/nanopb/releases/download/nanopb-0.4.9.1/nanopb-0.4.9.1-linux-x86.tar.gz
           tar xvzf nanopb-0.4.9.1-linux-x86.tar.gz
           mv nanopb-0.4.9.1-linux-x86 nanopb-0.4.9
 
@@ -33,7 +38,7 @@ jobs:
       - name: Create pull request
         uses: peter-evans/create-pull-request@v8
         with:
-          branch: create-pull-request/update-protobufs
+          branch: create-pull-request/update-protobufs-${{ github.ref_name }}
           labels: submodules
           title: Update protobufs and classes
           commit-message: Update protobufs

AGENTS.md

@@ -64,7 +64,7 @@ Key rotation to never trigger casually: only the **full** factory reset (`factor
 - **One MCP call per serial port at a time.** The port lock is exclusive; concurrent calls deadlock. Sequence: open → read/mutate → close, then next device.
 - **`userPrefs.jsonc` is session state during tests.** The `_session_userprefs` fixture snapshots + restores it; never edit it from inside a test.
 - **Don't speculate about firmware root causes.** When evidence doesn't support a classification, say "unknown" and list what would disambiguate.
-- **Run `trunk fmt` before proposing a commit.** The `trunk_check` CI gate will reject unformatted code.
+- **Run `trunk fmt` before proposing a commit.** The `trunk_check` CI gate will reject unformatted code. Claude Code runs it automatically via the PostToolUse hook in `.claude/settings.json`; trunk's launcher needs `curl` or `wget` to bootstrap its pinned CLI — see **Formatting & the trunk toolchain** in `.github/copilot-instructions.md` for the no-curl bootstrap procedure.
 - **`confirm=True` on destructive MCP tools is a real gate, not a formality.** Don't bypass it via auto-approve settings.
 - **Keep code comments minimal — one or two lines, max.** Comment only when the _why_ isn't obvious from the code; never restate what the next line does. No multi-paragraph block comments explaining straightforward changes. The diff and commit message carry the rationale; the code carries the behavior.
 - **Use `Throttle` for time-based rate limiting, not raw `millis()` math.** `src/mesh/Throttle.h` provides `Throttle::isWithinTimespanMs(lastMs, intervalMs)` (returns true while inside the cooldown) and `Throttle::execute(&lastMs, intervalMs, func)` (function-pointer form that updates the timestamp on fire). Use these for any "did N ms pass since X" check — raw `millis() > lastMs + N` is rollover-unsafe (breaks after ~49.7 days) and inconsistent with the rest of the codebase. The helpers compute `now - lastMs` with unsigned subtraction, which wraps correctly.

SECURITY.md

@@ -10,3 +10,35 @@
 ## Reporting a Vulnerability
 
 We support the private reporting of potential security vulnerabilities. Please go to the Security tab to file a report with a description of the potential vulnerability and reproduction scripts (preferred) or steps, and our developers will review.
+
+Before filing, please read the Security Model below. Behavior whose only precondition is local API access to a node, or possession of a channel's pre-shared key, is intended by design and is not considered a vulnerability.
+
+## Security Model
+
+Meshtastic is an off-grid mesh protocol that runs on constrained microcontrollers within a 256 byte LoRa packet limit. These constraints shape its security design and rule out the heavier schemes used by IP-based protocols. This section summarizes what the firmware protects, the assumptions it rests on, and its known limits. Fuller write-ups are in the documentation:
+
+- Encryption overview: https://meshtastic.org/docs/overview/encryption/
+- Technical reference: https://meshtastic.org/docs/development/reference/encryption-technical/
+- Known limitations and future work: https://meshtastic.org/docs/about/overview/encryption/limitations/
+
+### Cryptographic mechanisms
+
+- Channels are encrypted with a pre-shared key (PSK) using AES256-CTR. Channel traffic is encrypted but not authenticated, so anyone holding the PSK can read channel messages and can send messages as any node on that channel.
+- Direct messages and admin messages use public key cryptography (x25519 key exchange with AES-CCM), providing confidentiality, authentication, and integrity between nodes on 2.5.0 or newer that have exchanged keys.
+- Admin sessions use short-lived session IDs to limit replay of control messages.
+
+### Local trust boundary
+
+A client connected to a node over Bluetooth, USB serial, WiFi, or Ethernet has full local API access. From that connection it can read decrypted traffic, send messages as the node, change configuration (subject to managed mode), and read the node's private key for backup. This is intended behavior. The firmware trusts the local link the same way a phone or laptop trusts a directly attached device, and anything within reach of that connection (a shared LAN, a USB cable to an untrusted host, a paired phone) should be treated as part of the node itself.
+
+### Node identity (Trust On First Use)
+
+There is no central authority to sign node keys. The first public key a node hears for a given node number is the one it binds to that node number, a Trust On First Use (TOFU) model that is a hard requirement of a decentralized mesh. Clients and firmware reduce the impact of this by keeping favorited nodes from rolling out of the node database and by flagging public-key changes in the client UI.
+
+Firmware 2.8.X adds XEdDSA packet signing to further secure node identity claims and the authenticity of subsequent messages. It reuses each node's existing x25519 key pair to produce signatures, so a receiver can verify that a packet came from the holder of the bound key. Once a node has been seen signing, unsigned packets claiming that identity can be rejected.
+
+### Known limitations
+
+- No perfect forward secrecy. Traffic captured today can be decrypted later if a key is compromised, for example through a lost node or a mishandled channel key.
+- Channel messages are not authenticated, as noted above. Although as of 2.8, channel messages will be xedDSA signed as a means of verification that is non-breaking.
+- Setting WiFi credentials, or performing any other local administration, on an ESP32 over an untrusted network exposes that traffic, including the credentials, to the network. Provision and administer nodes over a trusted channel instead: Bluetooth, USB serial, or remote admin over the mesh. There is no current roadmap item to secure local administration over untrusted WiFi, though it may be addressed in a future release.

bin/config.d/lora-RAK6421-13300-slot2.yaml

@@ -5,7 +5,9 @@ Meta:
     - raspberry-pi
 
 Lora:
-  ### RAK13300 in Slot 2 pins
+  
+  ### RAK13300 in Slot 2
+  Module: sx1262
   IRQ: 18 #IO6
   Reset: 24 # IO4
   Busy: 19 # IO5
@@ -13,5 +15,7 @@ Lora:
   Enable_Pins:
     - 26
     - 23
+  DIO3_TCXO_VOLTAGE: true
+  DIO2_AS_RF_SWITCH: true
   spidev: spidev0.1
   # CS: 7

bin/config.d/lora-RAK6421-13302-slot2.yaml

@@ -5,14 +5,18 @@ Meta:
     - raspberry-pi
 
 Lora:
-  ### RAK13302 in Slot 2 pins
+
+  ### RAK13302 in Slot 2
+  Module: sx1262
   IRQ: 18 #IO6
   Reset: 24 # IO4
   Busy: 19 # IO5
-  # Ant_sw: 23 # IO3 
+  # Ant_sw: 23 # IO3
   Enable_Pins:
     - 26
     - 23
+  DIO3_TCXO_VOLTAGE: true
+  DIO2_AS_RF_SWITCH: true
   spidev: spidev0.1
   # CS: 7
   TX_GAIN_LORA: [9, 9, 10, 11, 9, 8, 9, 10, 10, 10, 11, 12, 12, 12, 12, 12, 12, 12, 12, 10, 9, 8]

bin/eth-ota-upload.py

@@ -0,0 +1,252 @@
+#!/usr/bin/env python3
+"""
+Meshtastic Ethernet OTA Upload Tool
+
+Uploads firmware to RP2350-based Meshtastic devices via Ethernet (W5500).
+Compresses firmware with GZIP and sends it over TCP using the MOTA protocol.
+Authenticates using SHA256 challenge-response with a pre-shared key (PSK).
+
+Usage:
+    python bin/eth-ota-upload.py --host 192.168.1.100 firmware.bin
+    python bin/eth-ota-upload.py --host 192.168.1.100 --psk mySecretKey firmware.bin
+    python bin/eth-ota-upload.py --host 192.168.1.100 --psk-hex 6d65736874... firmware.bin
+"""
+
+import argparse
+import gzip
+import hashlib
+import socket
+import struct
+import sys
+import time
+
+# Default PSK matching the firmware default: "meshtastic_ota_default_psk_v1!!!"
+DEFAULT_PSK = b"meshtastic_ota_default_psk_v1!!!"
+
+
+def crc32(data: bytes) -> int:
+    """Compute CRC32 matching ErriezCRC32 (standard CRC32 with final XOR)."""
+    import binascii
+
+    return binascii.crc32(data) & 0xFFFFFFFF
+
+
+def load_firmware(path: str) -> bytes:
+    """Load firmware file, compressing with GZIP if not already compressed."""
+    # Reject UF2 files — OTA requires raw .bin firmware
+    if path.lower().endswith(".uf2"):
+        bin_path = path.rsplit(".", 1)[0] + ".bin"
+        print(f"ERROR: UF2 files cannot be used for OTA updates.")
+        print(f"       The Updater/picoOTA expects raw .bin firmware.")
+        print(f"       Try: {bin_path}")
+        sys.exit(1)
+
+    with open(path, "rb") as f:
+        data = f.read()
+
+    # Check if already GZIP compressed (magic bytes 1f 8b)
+    if data[:2] == b"\x1f\x8b":
+        print(f"Firmware already GZIP compressed: {len(data):,} bytes")
+        return data
+
+    print(f"Firmware raw size: {len(data):,} bytes")
+    compressed = gzip.compress(data, compresslevel=9)
+    ratio = len(compressed) / len(data) * 100
+    print(f"GZIP compressed: {len(compressed):,} bytes ({ratio:.1f}%)")
+    return compressed
+
+
+def authenticate(sock: socket.socket, psk: bytes) -> bool:
+    """Perform SHA256 challenge-response authentication with the device."""
+    # Receive 32-byte nonce from server
+    nonce = b""
+    while len(nonce) < 32:
+        chunk = sock.recv(32 - len(nonce))
+        if not chunk:
+            print("ERROR: Connection closed during authentication")
+            return False
+        nonce += chunk
+
+    # Compute SHA256(nonce || PSK)
+    h = hashlib.sha256()
+    h.update(nonce)
+    h.update(psk)
+    response = h.digest()
+
+    # Send 32-byte response
+    sock.sendall(response)
+
+    # Wait for auth result (1 byte)
+    result = sock.recv(1)
+    if not result:
+        print("ERROR: No authentication response")
+        return False
+
+    if result[0] == 0x06:  # ACK
+        print("Authentication successful.")
+        return True
+    elif result[0] == 0x07:  # OTA_ERR_AUTH
+        print("ERROR: Authentication failed — wrong PSK")
+        return False
+    else:
+        print(f"ERROR: Unexpected auth response 0x{result[0]:02X}")
+        return False
+
+
+def upload_firmware(host: str, port: int, firmware: bytes, psk: bytes, timeout: float) -> bool:
+    """Upload firmware over TCP using the MOTA protocol with PSK authentication."""
+    fw_crc = crc32(firmware)
+    fw_size = len(firmware)
+
+    print(f"Connecting to {host}:{port}...")
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    sock.settimeout(timeout)
+
+    try:
+        sock.connect((host, port))
+        print("Connected.")
+
+        # Step 1: Authenticate
+        print("Authenticating...")
+        if not authenticate(sock, psk):
+            return False
+
+        # Step 2: Send 12-byte MOTA header: magic(4) + size(4) + crc32(4)
+        header = struct.pack("<4sII", b"MOTA", fw_size, fw_crc)
+        sock.sendall(header)
+        print(f"Header sent: size={fw_size:,}, CRC32=0x{fw_crc:08X}")
+
+        # Wait for ACK (1 byte)
+        ack = sock.recv(1)
+        if not ack or ack[0] != 0x06:
+            error_codes = {
+                0x02: "Size error",
+                0x04: "Invalid magic",
+                0x05: "Update.begin() failed",
+            }
+            code = ack[0] if ack else 0xFF
+            msg = error_codes.get(code, f"Unknown error 0x{code:02X}")
+            print(f"ERROR: Server rejected header: {msg}")
+            return False
+
+        print("Header accepted. Uploading firmware...")
+
+        # Send firmware in 1KB chunks
+        chunk_size = 1024
+        sent = 0
+        start_time = time.time()
+
+        while sent < fw_size:
+            end = min(sent + chunk_size, fw_size)
+            chunk = firmware[sent:end]
+            sock.sendall(chunk)
+            sent = end
+
+            # Progress bar
+            pct = sent * 100 // fw_size
+            bar_len = 40
+            filled = bar_len * sent // fw_size
+            bar = "█" * filled + "░" * (bar_len - filled)
+            elapsed = time.time() - start_time
+            speed = sent / elapsed if elapsed > 0 else 0
+            sys.stdout.write(f"\r  [{bar}] {pct:3d}% {sent:,}/{fw_size:,} ({speed/1024:.1f} KB/s)")
+            sys.stdout.flush()
+
+        elapsed = time.time() - start_time
+        print(f"\n  Transfer complete in {elapsed:.1f}s")
+
+        # Wait for final result (1 byte)
+        print("Waiting for verification...")
+        result = sock.recv(1)
+        if not result:
+            print("ERROR: No response from device")
+            return False
+
+        result_codes = {
+            0x00: "OK — Update staged, device rebooting",
+            0x01: "CRC mismatch",
+            0x02: "Size error",
+            0x03: "Write error",
+            0x04: "Magic mismatch",
+            0x05: "Updater.begin() failed",
+            0x07: "Auth failed",
+            0x08: "Timeout",
+        }
+        code = result[0]
+        msg = result_codes.get(code, f"Unknown result 0x{code:02X}")
+
+        if code == 0x00:
+            print(f"SUCCESS: {msg}")
+            return True
+        else:
+            print(f"ERROR: {msg}")
+            return False
+
+    except socket.timeout:
+        print("ERROR: Connection timed out")
+        return False
+    except ConnectionRefusedError:
+        print(f"ERROR: Connection refused by {host}:{port}")
+        return False
+    except OSError as e:
+        print(f"ERROR: {e}")
+        return False
+    finally:
+        sock.close()
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Upload firmware to Meshtastic RP2350 devices via Ethernet OTA"
+    )
+    parser.add_argument("firmware", help="Path to firmware .bin or .bin.gz file")
+    parser.add_argument("--host", required=True, help="Device IP address")
+    parser.add_argument(
+        "--port", type=int, default=4243, help="OTA port (default: 4243)"
+    )
+    parser.add_argument(
+        "--timeout",
+        type=float,
+        default=60.0,
+        help="Socket timeout in seconds (default: 60)",
+    )
+    psk_group = parser.add_mutually_exclusive_group()
+    psk_group.add_argument(
+        "--psk",
+        type=str,
+        help="Pre-shared key as UTF-8 string (default: meshtastic_ota_default_psk_v1!!!)",
+    )
+    psk_group.add_argument(
+        "--psk-hex",
+        type=str,
+        help="Pre-shared key as hex string (e.g., 6d65736874...)",
+    )
+    args = parser.parse_args()
+
+    # Resolve PSK
+    if args.psk:
+        psk = args.psk.encode("utf-8")
+    elif args.psk_hex:
+        try:
+            psk = bytes.fromhex(args.psk_hex)
+        except ValueError:
+            print("ERROR: Invalid hex string for --psk-hex")
+            sys.exit(1)
+    else:
+        psk = DEFAULT_PSK
+
+    print("Meshtastic Ethernet OTA Upload")
+    print("=" * 40)
+
+    firmware = load_firmware(args.firmware)
+
+    if upload_firmware(args.host, args.port, firmware, psk, args.timeout):
+        print("\nDevice is rebooting with new firmware.")
+        sys.exit(0)
+    else:
+        print("\nUpload failed.")
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()

bin/run-tests.sh

@@ -0,0 +1,249 @@
+#!/usr/bin/env bash
+# Run native PlatformIO unit tests and emit a single, unambiguous RED/AMBER/GREEN verdict.
+#
+# Why this exists: PlatformIO reports failures three different ways ([FAILED], :FAIL:,
+# [ERRORED]) and an all-pass run prints "N succeeded" with NO "0 failed" clause — so naive
+# greps produce false greens (see .notes/test-passfail-filter.md). This script encodes the
+# correct logic once, and cross-checks the number of suites that actually ran against the
+# canonical set in test/ so a suite silently going missing shows up as AMBER, not green.
+#
+# Usage:
+#   ./bin/run-tests.sh                      # run all suites, full RAG + count cross-check
+#   ./bin/run-tests.sh -f test_utf8         # run one suite (no count cross-check)
+#   ./bin/run-tests.sh -e native            # override env (default: coverage)
+#   ./bin/run-tests.sh --quiet              # only print the final RESULT line
+#
+# Exit codes: 0 = GREEN, 1 = RED, 2 = AMBER.
+#
+# The final line is machine-readable, e.g.:
+#   RESULT: GREEN 19/19 suites passed
+#   RESULT: AMBER 17/19 suites ran (missing: test_radio test_serial) — all that ran passed
+#   RESULT: RED test_traffic_management: 1 failed  (or: build/crash error)
+#   RESULT: RED sanitizer fault — SUMMARY: AddressSanitizer: 1272 byte(s) leaked  (tests may have
+#           all passed; the coverage build aborts at exit on an ASan/LSan fault — often shown only
+#           as [ERRORED]/SIGHUP. The script names it and points at running the binary bare.)
+
+set -uo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+ROOT_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
+cd "$ROOT_DIR"
+
+ENV="coverage"
+FILTER=""
+QUIET=false
+PASSTHRU=()
+
+while [[ $# -gt 0 ]]; do
+	case "$1" in
+	-f)
+		FILTER="$2"
+		PASSTHRU+=("-f" "$2")
+		shift 2
+		;;
+	-e)
+		ENV="$2"
+		shift 2
+		;;
+	--quiet)
+		QUIET=true
+		shift
+		;;
+	*)
+		PASSTHRU+=("$1")
+		shift
+		;;
+	esac
+done
+
+# Locate pio (PATH, then the standard PlatformIO venv).
+PIO="$(command -v pio || command -v platformio || echo "$HOME/.platformio/penv/bin/pio")"
+if [[ ! -x $PIO ]] && ! command -v "$PIO" >/dev/null 2>&1; then
+	echo "RESULT: RED pio not found (looked in PATH and ~/.platformio/penv/bin)"
+	exit 1
+fi
+
+LOG="$(mktemp -t meshtest.XXXXXX.log)"
+MARKER=""
+PROGRESS_PID=""
+trap 'rm -f "$LOG" "${MARKER:-}"; [[ -n ${PROGRESS_PID:-} ]] && kill "$PROGRESS_PID" 2>/dev/null' EXIT
+
+# Canonical suite set = the directories in test/. This is the source of truth for
+# "what should run"; a filtered run only expects its filtered suite.
+mapfile -t ALL_SUITES < <(find test -maxdepth 1 -type d -name 'test_*' -printf '%f\n' | sort)
+EXPECTED_COUNT=${#ALL_SUITES[@]}
+
+# Cached object-count for this env, written after each completed build (in the gitignored build
+# dir). Used as the progress denominator: accurate for a full rebuild (every object recompiles),
+# only a rough upper bound for an incremental run.
+BASELINE_FILE=".pio/build/${ENV}/.runtests-objcount"
+
+# Progress trail file (gitignored build dir). ALWAYS written so a backgrounded/piped run can be
+# checked mid-build with `tail -f` — that's the whole point: don't fly blind on a 20-min rebuild.
+PROGRESS_FILE=".pio/build/${ENV}/.runtests-progress"
+
+# --- Progress heartbeat ------------------------------------------------------
+# Emit ONE status line every few seconds: build = objects (re)compiled this run / cached total +
+# best-effort ETA; test = suites finished / expected. Appends to $PROGRESS_FILE always (tail it to
+# check on a backgrounded run); also live-updates the tty when $5=1 (interactive --quiet). Never
+# touches $LOG, which is parsed for the verdict, so piped/CI captures stay clean.
+progress_monitor() {
+	local marker="$1" objtotal="$2" testtotal="$3" pfile="$4" totty="$5" start now el done ran eta line
+	start=$(date +%s)
+	while :; do
+		now=$(date +%s)
+		el=$((now - start))
+		if grep -q 'Testing\.\.\.' "$LOG" 2>/dev/null; then
+			ran=$(grep -cE "${ENV}:test_[a-z0-9_]+ \[(PASSED|FAILED|ERRORED)\]" "$LOG" 2>/dev/null)
+			line=$(printf '[test] %s/%s suites done — %dm%02ds' "$ran" "$testtotal" $((el / 60)) $((el % 60)))
+		else
+			done=$(find ".pio/build/${ENV}" -name '*.o' -newer "$marker" 2>/dev/null | wc -l)
+			if ((objtotal > 0 && done > 0)); then
+				eta=$((objtotal > done ? (objtotal - done) * el / done : 0))
+				line=$(printf '[build] %d/%d objs — %dm%02ds — ETA ~%dm%02ds' \
+					"$done" "$objtotal" $((el / 60)) $((el % 60)) $((eta / 60)) $((eta % 60)))
+			else
+				# done==0 (incremental: nothing to rebuild yet) or no cached baseline — no ETA yet.
+				line=$(printf '[build] %d objs compiled — %dm%02ds' "$done" $((el / 60)) $((el % 60)))
+			fi
+		fi
+		printf '%s\n' "$line" >>"$pfile" 2>/dev/null                           # file trail (always)
+		[[ $totty == 1 ]] && printf '\r\033[K%s' "$line" >/dev/tty 2>/dev/null # live line (human)
+		sleep 4
+	done
+}
+
+# Launch the heartbeat for every run. It writes the progress file unconditionally; the live tty
+# line only when interactive AND --quiet (where pio's own output is hidden — otherwise pio's
+# streamed compile lines already show progress and a \r line would just fight them).
+mkdir -p ".pio/build/${ENV}" 2>/dev/null || true
+: >"$PROGRESS_FILE" 2>/dev/null || true
+MARKER="$(mktemp -t meshtest-mark.XXXXXX)"
+TOTTY=0
+{ $QUIET && [[ -t 1 ]]; } && TOTTY=1
+progress_monitor "$MARKER" "$(cat "$BASELINE_FILE" 2>/dev/null || echo 0)" \
+	"$([[ -n $FILTER ]] && echo 1 || echo "$EXPECTED_COUNT")" "$PROGRESS_FILE" "$TOTTY" &
+PROGRESS_PID=$!
+
+if ! $QUIET; then
+	echo "Running: $PIO test -e $ENV ${PASSTHRU[*]-} (expecting $EXPECTED_COUNT suites)"
+fi
+echo "progress: tail -f $PROGRESS_FILE" >&2
+
+# Run pio, tee to log. PIPESTATUS[0] is pio's real exit (NOT tee's).
+if $QUIET; then
+	"$PIO" test -e "$ENV" "${PASSTHRU[@]}" >"$LOG" 2>&1
+else
+	"$PIO" test -e "$ENV" "${PASSTHRU[@]}" 2>&1 | tee "$LOG"
+fi
+PIO_RC=${PIPESTATUS[0]}
+
+# Stop the heartbeat, clear its line, and cache this build's object total for next time.
+if [[ -n $PROGRESS_PID ]]; then
+	kill "$PROGRESS_PID" 2>/dev/null
+	wait "$PROGRESS_PID" 2>/dev/null
+	PROGRESS_PID=""
+	# Clear the live line only if we were writing one — opening /dev/tty when there is none is
+	# itself a redirect-open error the trailing 2>/dev/null cannot suppress.
+	[[ $TOTTY == 1 ]] && printf '\r\033[K' >/dev/tty 2>/dev/null
+fi
+[[ -d ".pio/build/${ENV}" ]] && find ".pio/build/${ENV}" -name '*.o' 2>/dev/null | wc -l >"$BASELINE_FILE" 2>/dev/null || true
+
+# --- Outcome detection -------------------------------------------------------
+# The SAME outcome is spelled differently depending on which layer emitted the line — this is
+# the trap that produces false greens (grepping ":PASS" misses pio's "[PASSED]", grepping
+# "[FAILED]" misses Unity's ":FAIL:"). So every regex below matches BOTH spellings:
+#   pass:  Unity per-assertion ":PASS"   | pio per-suite "[PASSED]"      | summary "N succeeded"
+#   fail:  Unity per-assertion ":FAIL:"  | pio per-suite "[FAILED]"      | summary "M failed"
+#   error: pio build/crash "[ERRORED]"   | Unity "M Failures"            | compiler "error:"
+# Match \b after :PASS/:FAIL so ":PASSED"/":FAILED" forms are also caught either way.
+FAIL_RE=':FAIL\b|\[FAILED\]|\[ERRORED\]|[1-9][0-9]* failed|[0-9]+ Tests [1-9][0-9]* Failures|error:|undefined reference|Segmentation fault|terminate called|SIGHUP|SIGSEGV|SIGABRT'
+# Positive proof tests actually ran & passed (absence != success). Accept any pass spelling:
+# the per-test/per-suite tokens OR a success summary line.
+PASS_RE=':PASS\b|\[PASSED\]|test cases: *[0-9]+ succeeded|[0-9]+ Tests 0 Failures'
+# Sanitizer (ASan/LSan/UBSan/TSan) fault signatures. The coverage build is sanitizer-instrumented
+# and aborts NON-ZERO at exit on a fault — most often a LeakSanitizer leak — AFTER every test has
+# already printed [PASSED]. pio then reports [ERRORED]/SIGHUP with no :FAIL: anywhere, so it
+# masquerades as a phantom "N-1 of N succeeded". See .notes/test-passfail-filter.md.
+# Match only real FAULT lines, never the benign "AddressSanitizer: failed to intercept '...'"
+# startup noise that prints on every sanitizer run (it'd mislabel a normal [FAILED] as a leak).
+# Formats per LLVM/Google sanitizer docs: ASan/LSan emit "==PID==ERROR: <San>: ...", UBSan emits
+# "file:line:col: runtime error: ...", TSan emits "WARNING: ThreadSanitizer: ..."; all close with
+# a "SUMMARY: <San>: ..." line (LSan-under-ASan reports its SUMMARY as "AddressSanitizer").
+SAN_RE='(ERROR|WARNING): (Address|Leak|Thread|UndefinedBehavior)Sanitizer:|SUMMARY: (Address|Leak|Thread|UndefinedBehavior)Sanitizer:|Direct leak of|Indirect leak of|detected memory leaks|heap-use-after-free|heap-buffer-overflow|stack-buffer-overflow|attempting double-free|LeakSanitizer has encountered a fatal error|runtime error:'
+
+# Suites that produced a per-suite verdict. pio emits "coverage:test_x [PASSED|FAILED|ERRORED]";
+# a SKIPPED suite (hardware-only on native) is "accounted for" too, so it doesn't read as missing.
+mapfile -t RAN_SUITES < <(grep -oE "${ENV}:test_[a-z0-9_]+ \[(PASSED|FAILED|ERRORED)\]" "$LOG" |
+	sed -E "s/^${ENV}:(test_[a-z0-9_]+) .*/\1/" | sort -u)
+RAN_COUNT=${#RAN_SUITES[@]}
+# Suites pio explicitly skipped (don't count these as "missing" in the canonical cross-check).
+mapfile -t SKIPPED_SUITES < <(grep -oE "${ENV}:test_[a-z0-9_]+.*\bSKIPPED\b" "$LOG" |
+	grep -oE "test_[a-z0-9_]+" | sort -u)
+
+verdict_red() {
+	local detail bin
+	detail="$(grep -nE '\[FAILED\]|:FAIL:|\[ERRORED\]' "$LOG" | head -3 | sed 's/^/    /')"
+	echo ""
+	echo "RED — failures detected:"
+	[[ -n $detail ]] && echo "$detail"
+	grep -E 'test cases:' "$LOG" | tail -1 | sed 's/^/    /'
+
+	# Path to the test binary for the "run it bare" hint. For native/coverage the test program is
+	# the env executable (e.g. .pio/build/coverage/meshtasticd), NOT a file named 'program'.
+	bin="$(find ".pio/build/${ENV}" -maxdepth 1 -type f -executable ! -name '*.so' 2>/dev/null | head -1)"
+	[[ -z $bin ]] && bin=".pio/build/${ENV}/<program>  (build it first: $PIO test -e ${ENV} ${FILTER:+-f $FILTER} --without-testing)"
+
+	# Sanitizer fault (ASan/LSan/UBSan/TSan): name the real cause instead of "build/crash error".
+	if grep -qE "$SAN_RE" "$LOG"; then
+		grep -nE "$SAN_RE" "$LOG" | head -4 | sed 's/^/    /'
+		echo "    -> sanitizer fault: if every test above is PASS, this is an exit-time abort, not a failed assertion."
+		echo "    -> read the full report by running the binary BARE (gdb hides it via ptrace): ./$bin 2>&1 | tail -40"
+		echo "RESULT: RED sanitizer fault — $(grep -ohE 'SUMMARY: [A-Za-z]+Sanitizer:.*' "$LOG" | tail -1 || echo 'see report above')"
+		exit 1
+	fi
+
+	# All tests passed but the process still aborted at EXIT (ERRORED/SIGHUP/SIGABRT) and the
+	# sanitizer report was swallowed by the runner (often surfaced only as SIGHUP). Almost always a
+	# sanitizer fault — point at how to surface it rather than calling it a generic crash.
+	if grep -qE "$PASS_RE" "$LOG" && grep -qE '\[ERRORED\]|SIGHUP|SIGABRT' "$LOG" && ! grep -qE ':FAIL\b|\[FAILED\]' "$LOG"; then
+		echo "    -> all tests passed but the process aborted at EXIT — likely an ASan/LSan fault whose report"
+		echo "       the runner swallowed (commonly shown as SIGHUP). Run the binary BARE to see it: ./$bin 2>&1 | tail -40"
+		echo "RESULT: RED exit-time abort (tests passed; likely sanitizer — see hint above)"
+		exit 1
+	fi
+
+	echo "RESULT: RED $(grep -oE '[0-9]+ failed' "$LOG" | tail -1 || echo 'build/crash error')"
+	exit 1
+}
+
+# RED: pio non-zero, any failure marker, or no positive summary at all (build died early).
+if [[ $PIO_RC -ne 0 ]] || grep -qE "$FAIL_RE" "$LOG"; then
+	verdict_red
+fi
+if ! grep -qE "$PASS_RE" "$LOG"; then
+	echo ""
+	echo "RESULT: RED no success summary found (build error / no tests ran?) — see log"
+	exit 1
+fi
+
+# AMBER: everything that ran passed, but (full run only) a canonical suite neither ran NOR was
+# explicitly skipped — i.e. it silently went missing. SKIPPED suites are accounted for.
+ACCOUNTED_COUNT=$((RAN_COUNT + ${#SKIPPED_SUITES[@]}))
+if [[ -z $FILTER && $ACCOUNTED_COUNT -lt $EXPECTED_COUNT ]]; then
+	missing=()
+	for s in "${ALL_SUITES[@]}"; do
+		printf '%s\n' "${RAN_SUITES[@]}" "${SKIPPED_SUITES[@]}" | grep -qx "$s" || missing+=("$s")
+	done
+	echo ""
+	echo "RESULT: AMBER ${RAN_COUNT}/${EXPECTED_COUNT} suites ran (missing: ${missing[*]}) — all that ran passed"
+	exit 2
+fi
+
+# GREEN.
+if [[ -n $FILTER ]]; then
+	echo "RESULT: GREEN ${RAN_COUNT} suite(s) passed (filtered: $FILTER)"
+else
+	echo "RESULT: GREEN ${RAN_COUNT}/${EXPECTED_COUNT} suites passed"
+fi
+exit 0

boards/heltec_mesh_tower_v2.json

@@ -0,0 +1,54 @@
+{
+  "build": {
+    "arduino": {
+      "ldscript": "nrf52840_s140_v6.ld"
+    },
+    "core": "nRF5",
+    "cpu": "cortex-m4",
+    "extra_flags": "-DNRF52840_XXAA",
+    "f_cpu": "64000000L",
+    "hwids": [
+      ["0x239A", "0x4405"],
+      ["0x239A", "0x0029"],
+      ["0x239A", "0x002A"],
+      ["0x239A", "0x0071"]
+    ],
+    "usb_product": "HT-n5262",
+    "mcu": "nrf52840",
+    "variant": "heltec_mesh_tower_v2",
+    "variants_dir": "variants",
+    "bsp": {
+      "name": "adafruit"
+    },
+    "softdevice": {
+      "sd_flags": "-DS140",
+      "sd_name": "s140",
+      "sd_version": "6.1.1",
+      "sd_fwid": "0x00B6"
+    },
+    "bootloader": {
+      "settings_addr": "0xFF000"
+    }
+  },
+  "connectivity": ["bluetooth"],
+  "debug": {
+    "jlink_device": "nRF52840_xxAA",
+    "onboard_tools": ["jlink"],
+    "svd_path": "nrf52840.svd",
+    "openocd_target": "nrf52840-mdk-rs"
+  },
+  "frameworks": ["arduino"],
+  "name": "Heltec MeshTower V2 (Adafruit BSP)",
+  "upload": {
+    "maximum_ram_size": 248832,
+    "maximum_size": 815104,
+    "speed": 115200,
+    "protocol": "nrfutil",
+    "protocols": ["jlink", "nrfjprog", "nrfutil", "stlink"],
+    "use_1200bps_touch": true,
+    "require_upload_port": true,
+    "wait_for_upload_port": true
+  },
+  "url": "https://heltec.org",
+  "vendor": "Heltec"
+}

boards/wiscore_rak4600.json

@@ -1,50 +0,0 @@
-{
-  "build": {
-    "arduino": {
-      "ldscript": "nrf52832_s132_v6.ld"
-    },
-    "core": "nRF5",
-    "cpu": "cortex-m4",
-    "extra_flags": "-DNRF52832_XXAA -DNRF52",
-    "f_cpu": "64000000L",
-    "hwids": [
-      ["0x239A", "0x8029"],
-      ["0x239A", "0x0029"],
-      ["0x239A", "0x002A"],
-      ["0x239A", "0x802A"]
-    ],
-    "usb_product": "Feather nRF52832 Express",
-    "mcu": "nrf52832",
-    "variant": "WisCore_RAK4600_Board",
-    "bsp": {
-      "name": "adafruit"
-    },
-    "softdevice": {
-      "sd_flags": "-DS132",
-      "sd_name": "s132",
-      "sd_version": "6.1.1",
-      "sd_fwid": "0x00B7"
-    },
-    "zephyr": {
-      "variant": "nrf52_adafruit_feather"
-    }
-  },
-  "connectivity": ["bluetooth"],
-  "debug": {
-    "jlink_device": "nRF52832_xxAA",
-    "svd_path": "nrf52.svd",
-    "openocd_target": "nrf52840-mdk-rs"
-  },
-  "frameworks": ["arduino", "zephyr"],
-  "name": "Adafruit Bluefruit nRF52832 Feather",
-  "upload": {
-    "maximum_ram_size": 65536,
-    "maximum_size": 524288,
-    "require_upload_port": true,
-    "speed": 115200,
-    "protocol": "nrfutil",
-    "protocols": ["jlink", "nrfjprog", "nrfutil", "stlink"]
-  },
-  "url": "https://www.adafruit.com/product/3406",
-  "vendor": "Adafruit"
-}

docs/lora_region_preset_compatibility_client_spec.md

@@ -0,0 +1,277 @@
+# LoRa Region → Preset Compatibility — Client Implementation Spec
+
+**Status:** Draft for 2.8 · **Audience:** Meshtastic client app developers (Android first,
+Apple second, then web/python) · **Firmware side:** implemented in `firmware`
+(`FromRadio.region_presets`, see below).
+
+> This document lives in the firmware repo while the feature is developed. It is meant to
+> graduate to `meshtastic/protobufs` (and/or the docs site) alongside the upstream protobuf
+> PR that reserves `FromRadio` field **19**.
+
+---
+
+## 1. Why this exists
+
+For 2.8 the LoRa regions and modem presets were reworked. **Not every modem preset is legal
+in every region** — narrow EU SRD bands, the EU 868 "narrow" band, amateur/ham bands, and
+the 2.4 GHz band each accept only a specific subset of presets. The firmware already
+enforces this internally (it clamps or rejects illegal combinations), but until now a client
+had no way to _know_ the rules, so a user could pick an illegal region+preset pair in the UI
+and only discover the problem after the device silently corrected it.
+
+This feature has the firmware **declare the legal region→preset combinations** to the client
+during the `want_config` handshake, so the client UI can constrain the preset picker to the
+valid set for the currently selected region (and warn about licensed-only bands). It is
+purely advisory metadata — the firmware remains the source of truth and still
+validates/clamps on its own.
+
+---
+
+## 2. Protocol additions
+
+Three new messages in `meshtastic/mesh.proto`, plus one new `FromRadio` oneof variant.
+
+### 2.1 `FromRadio.region_presets` (field 19)
+
+```proto
+message FromRadio {
+  uint32 id = 1;
+  oneof payload_variant {
+    // ... fields 2..18 unchanged ...
+    LoRaRegionPresetMap region_presets = 19;
+  }
+}
+```
+
+### 2.2 Messages
+
+```proto
+// A distinct set of legal modem presets shared by one or more LoRa regions.
+message LoRaPresetGroup {
+  repeated Config.LoRaConfig.ModemPreset presets = 1;       // legal presets for this group
+  Config.LoRaConfig.ModemPreset         default_preset = 2; // always one of `presets`
+  bool                                  licensed_only = 3;  // ham/amateur band → warn/gate
+}
+
+// Associates a single LoRa region with its preset group (by index).
+message LoRaRegionPresets {
+  Config.LoRaConfig.RegionCode region = 1;
+  uint32                       group_index = 2; // index into LoRaRegionPresetMap.groups
+}
+
+// The full map, delivered grouped to fit one FromRadio packet.
+message LoRaRegionPresetMap {
+  repeated LoRaPresetGroup    groups = 1;        // each distinct preset list
+  repeated LoRaRegionPresets  region_groups = 2; // every known region → a group index
+}
+```
+
+### 2.3 Why grouped (and the size envelope clients should respect)
+
+A `FromRadio` packet is capped at **512 bytes** (`MAX_TO_FROM_RADIO_SIZE`). Most regions
+share one identical preset list (the "standard" 9-preset list), so the map is delivered
+**grouped**: `groups` holds each _distinct_ preset list once, and `region_groups` maps every
+known region to one of those groups by index. This keeps the encoded size additive
+(`groups` + `region_groups`) rather than multiplicative, well under the cap.
+
+nanopb (firmware) array bounds — clients do **not** need to enforce these, but they bound
+what you can receive:
+
+| field                               | max_count                            |
+| ----------------------------------- | ------------------------------------ |
+| `LoRaRegionPresetMap.groups`        | 8                                    |
+| `LoRaRegionPresetMap.region_groups` | 38 (= number of `RegionCode` values) |
+| `LoRaPresetGroup.presets`           | 11                                   |
+
+---
+
+## 3. When it is delivered
+
+`region_presets` is sent **once** during the `want_config` handshake, as a single
+`FromRadio` message, in this position:
+
+```text
+my_info → (deviceuiConfig) → node_info(self) → metadata → region_presets → channel… → config… → moduleConfig… → node_info(others)… → fileInfo… → config_complete_id → (live packets)
+```
+
+i.e. **immediately after `metadata` and before the first `channel`**.
+
+- It is included for a normal full `want_config` and for the **config-only** nonce.
+- It is **omitted** for the **nodes-only** nonce (that path skips metadata/config entirely).
+- A client must **not** assume it always arrives (see §5).
+
+---
+
+## 4. Decoding into a usable lookup
+
+Flatten the grouped wire form into `Map<RegionCode, RegionPresetInfo>`:
+
+```text
+struct RegionPresetInfo { Set<ModemPreset> presets; ModemPreset default; bool licensedOnly }
+
+fun decode(map: LoRaRegionPresetMap): Map<RegionCode, RegionPresetInfo> {
+  result = {}
+  for (rg in map.region_groups) {
+    if (rg.group_index >= map.groups.size) continue   // defensive: malformed/forward data
+    g = map.groups[rg.group_index]
+    result[rg.region] = RegionPresetInfo(
+      presets = g.presets.toSet(),
+      default = g.default_preset,
+      licensedOnly = g.licensed_only)
+  }
+  return result
+}
+```
+
+Persist this map alongside the rest of the downloaded config so the LoRa config screen can
+read it synchronously.
+
+---
+
+## 5. Semantics & rules (the load-bearing part)
+
+These rules are what keep the UX correct across firmware versions. Implement all of them.
+
+1. **Absent region ⇒ no constraint.** If a `RegionCode` does not appear in `region_groups`,
+   the client has _no_ compatibility info for it and **must not restrict** its preset
+   choices (fall back to allowing the full `ModemPreset` list). This happens for a handful
+   of `RegionCode` enum values that have no firmware band table entry (today: `EU_874`,
+   `EU_917`, `ITU1_70CM`, `ITU2_70CM`, `ITU3_70CM`).
+
+2. **Absent message ⇒ no constraint.** Firmware older than 2.8 never sends `region_presets`.
+   New clients **must** tolerate the message being absent entirely and keep their existing
+   (unconstrained) behavior. Do not block the config screen waiting for it.
+
+3. **`default_preset`** is always a member of that group's `presets`. Use it to pre-select a
+   preset when the user switches to a region whose valid set does not include the currently
+   selected preset (instead of leaving an illegal selection or guessing).
+
+4. **`licensed_only`** marks ham/amateur bands. Surface a warning or gate (the firmware also
+   requires the operator's `is_licensed` flag for these regions; coordinate the two so the
+   user isn't allowed to pick a licensed band without acknowledging licensing).
+
+5. **EU region auto-swap caveat.** The firmware treats the EU sibling regions
+   (`EU_868` / `EU_866` / `EU_N_868`) specially: if the user is in one of them and selects a
+   preset that belongs to a sibling's list, the firmware **swaps the region** rather than
+   rejecting the preset. Consequence for clients: **do not assume the region is immutable
+   across a preset change** — after an admin config write, re-read the resulting
+   `LoRaConfig` and reflect the (possibly changed) region back into the UI.
+
+6. **Use it as a UI guard, not a validator of truth.** The firmware still validates/clamps
+   on its own. The map exists to prevent the user from _selecting_ an illegal combo; it is
+   not a security or correctness boundary.
+
+---
+
+## 6. UI/UX recommendations
+
+- In the LoRa config screen, when a region is selected, **filter/enable the modem-preset
+  picker to that region's `presets`** (when `use_preset`/`use_modem_preset` is on).
+- If the current preset is not in the newly selected region's set, switch the selection to
+  that region's `default_preset`.
+- Show a **licensed badge / confirmation** for regions where `licensed_only == true`.
+- If a region is absent from the map (rule §5.1) or the whole message is absent (§5.2),
+  render the full preset list as before — never show an empty picker.
+
+---
+
+## 7. Forward / backward compatibility
+
+- **Old clients, new firmware:** an unknown `FromRadio` oneof variant (field 19) is ignored
+  by protobuf/nanopb decoders; the relative ordering of the known messages is unchanged, so
+  existing apps are unaffected.
+- **New clients, old firmware:** message simply never arrives → treat as "no constraints"
+  (§5.2).
+- **Enum growth:** new `RegionCode`/`ModemPreset` values may appear over time. Decoders
+  should pass through unknown enum values rather than crashing; an unknown region in
+  `region_groups` is harmless (the client just won't have a localized name for it).
+
+---
+
+## 8. Platform notes
+
+> Verified against the `main` branch of each repo. Both have been refactored away from
+> older layouts; re-pin file paths against a specific commit if you need them durable.
+
+### 8.1 Android — `meshtastic/Meshtastic-Android` (Kotlin / Compose, KMP)
+
+- **Protobufs are a published Maven artifact, _not_ a submodule.** Declared in
+  `gradle/libs.versions.toml` (`org.meshtastic:protobufs`, currently `2.7.25`); generated
+  package is **`org.meshtastic.proto`**. **A `region_presets`-aware build requires a new
+  published `org.meshtastic:protobufs` release**, then bumping that one version string.
+- **The protobufs are Wire-generated**, so the `FromRadio` oneof is **not** a
+  `payloadVariantCase` enum — each arm is a **nullable field**. Handle the new variant in
+  `FromRadioPacketHandlerImpl.handleFromRadio(...)`
+  (`core/data/.../manager/FromRadioPacketHandlerImpl.kt`) by adding a
+  `regionPresets != null -> …` arm to the existing `when { … }`, delegating to a handler
+  (mirror `handleLocalMetadata` / `handleConfigComplete`).
+- **State holder:** expose the decoded map from `RadioConfigRepository` /
+  `RadioConfigRepositoryImpl` as a `Flow` (mirroring `localConfigFlow`/`channelSetFlow`),
+  consumed by `feature/settings/.../radio/RadioConfigViewModel.kt`.
+- **UI:** the region & preset dropdowns are `DropDownPreference`s in
+  `feature/settings/.../radio/component/LoRaConfigItemList.kt` (public composable
+  `LoRaConfigScreen`). Gate/filter the `ChannelOption` (preset) dropdown by the selected
+  `RegionInfo`'s entry in the map.
+
+### 8.2 Apple — `meshtastic/Meshtastic-Apple` (Swift / SwiftUI)
+
+- **Protobufs are vendored** into a local Swift package `MeshtasticProtobufs`
+  (`MeshtasticProtobufs/Sources/meshtastic/*.pb.swift`), generated from the `protobufs` git
+  submodule via `scripts/gen_protos.sh`. **To get field 19:** advance the `protobufs`
+  submodule, run `scripts/gen_protos.sh`, commit the regenerated `.pb.swift` + submodule
+  pointer. (No published-artifact dependency — Apple can regenerate from any commit.)
+- **Dispatch:** `AccessoryManager.processFromRadio(_:)`
+  (`Meshtastic/Accessory/Accessory Manager/AccessoryManager.swift`) is a real
+  `switch decodedInfo.payloadVariant { … }` — add a `.regionPresets` case, with the handler
+  in `AccessoryManager+FromRadio.swift` (mirror `handleConfig` / `handleMetadata`).
+- **Persistence:** config is **SwiftData** (`@Model` entities), upserted via
+  `MeshPackets`/`UpdateSwiftData.swift`. Store the decoded map (e.g. on a settings/connection
+  model) so the LoRa view can read it.
+- **UI:** `Meshtastic/Views/Settings/Config/LoRaConfig.swift` (`struct LoRaConfig: View`)
+  has the `Picker("Region", …)` (`RegionCodes.userSelectable`) and `Picker("Presets", …)`
+  (`ModemPresets.userSelectable`, gated on `usePreset`). Filter the presets picker by the
+  selected region's entry. Enums live in `Meshtastic/Enums/LoraConfigEnums.swift`.
+
+### 8.3 Other clients
+
+- **python (`meshtastic` / Meshtastic-python)** and **web** consume the published protobufs;
+  they will see `region_presets` once their protobuf dependency includes field 19, and can
+  ignore it until then (it decodes as an unknown field).
+
+---
+
+## 9. Reference payload (current firmware table)
+
+For decoder unit tests. With the 2.8 region table, the firmware emits **6 groups**. Group
+indices are assigned in region-table order (first region to use a profile creates its group),
+so they are stable as listed here:
+
+| group_index             | default_preset | licensed_only | presets                                                                                                        |
+| ----------------------- | -------------- | ------------- | -------------------------------------------------------------------------------------------------------------- |
+| 0 (standard)            | `LONG_FAST`    | false         | LONG_FAST, LONG_SLOW, MEDIUM_SLOW, MEDIUM_FAST, SHORT_SLOW, SHORT_FAST, LONG_MODERATE, SHORT_TURBO, LONG_TURBO |
+| 1 (EU 868)              | `LONG_FAST`    | false         | LONG_FAST, LONG_SLOW, MEDIUM_SLOW, MEDIUM_FAST, SHORT_SLOW, SHORT_FAST, LONG_MODERATE                          |
+| 2 (EU 866 SRD / "lite") | `LITE_FAST`    | false         | LITE_FAST, LITE_SLOW                                                                                           |
+| 3 (EU 868 narrow)       | `NARROW_SLOW`  | false         | NARROW_FAST, NARROW_SLOW                                                                                       |
+| 4 (ham 20 kHz)          | `TINY_FAST`    | **true**      | TINY_FAST, TINY_SLOW                                                                                           |
+| 5 (ham 100 kHz)         | `NARROW_SLOW`  | **true**      | NARROW_FAST, NARROW_SLOW                                                                                       |
+
+`region_groups` (region → group_index):
+
+| group | regions                                                                                                                                                               |
+| ----- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| 0     | US, EU_433, CN, JP, ANZ, ANZ_433, RU, KR, TW, IN, NZ_865, TH, UA_433, UA_868, MY_433, MY_919, SG_923, PH_433, PH_868, PH_915, KZ_433, KZ_863, NP_865, BR_902, LORA_24 |
+| 1     | EU_868                                                                                                                                                                |
+| 2     | EU_866                                                                                                                                                                |
+| 3     | EU_N_868                                                                                                                                                              |
+| 4     | ITU1_2M, ITU2_2M, ITU3_2M                                                                                                                                             |
+| 5     | ITU2_125CM                                                                                                                                                            |
+
+> Note groups **3** and **5** carry the same preset list (NARROW\_\*) but are distinct groups
+> because they differ in `licensed_only`. Decoders must key on the group, not on the preset
+> list, to preserve the licensing flag.
+>
+> Regions **absent** from the table (no constraint info; see §5.1): `EU_874`, `EU_917`,
+> `ITU1_70CM`, `ITU2_70CM`, `ITU3_70CM`.
+
+This table is generated from the firmware's region table at runtime; treat the firmware as
+authoritative and these values as the expected snapshot for the 2.8 table.

docs/nexthop-routing-reliability.md

@@ -0,0 +1,456 @@
+# NextHop direct-message reliability on dense meshes — findings & plan
+
+**Status:** Implemented — mitigations and tests in `PR3-tmm-nexthop`
+**Date:** 2026-06-13
+**Area:** `src/mesh` router stack (`NextHopRouter`, `ReliableRouter`, `FloodingRouter`, `Router`, `NodeDB`, `PacketHistory`)
+**Constraint:** No over-the-air / wire-format changes — `next_hop` and `relay_node` stay 1 byte, no `PacketHeader` changes, no breaking protobuf changes. All new state is RAM-only.
+
+This document captures the analysis and the proposed mitigations so the work can be
+continued on this branch by anyone. It is intentionally code-grounded (file:line
+references throughout) and standalone — you should not need the original investigation
+context to pick it up.
+
+---
+
+## TL;DR
+
+NextHop routing for direct messages (DMs) is unreliable on dense meshes. The headline
+cause is the **birthday problem**: `next_hop` and `relay_node` are each a single byte
+(the last byte of a 32-bit node number), so on a mesh of N nodes the probability that
+two share the same byte hits ~50% at **~19 nodes** and is near-certain by 50–100. But
+there are **other, equally important issues**: that single byte is trusted blindly at
+five different code sites, learned routes **never decay**, routes are learned from the
+**reverse (ACK) path** (asymmetric-link hazard), and collision-driven spurious
+rebroadcasts **amplify congestion** exactly when the mesh is busy.
+
+Because we can't widen the on-wire field, the fix is **interpretation-side** ("don't
+trust a byte that doesn't map to a unique reachable neighbor — flood instead") plus
+**recovery-side** ("decay stale/failing routes so they get re-discovered"). Four
+mitigations, M1–M4, all RAM-only. The net behavioral change: on dense/mobile meshes a
+DM that today silently misroutes or black-holes instead falls back to managed flooding
+(which still delivers) and re-learns a fresh route quickly. Sparse-mesh happy paths are
+unchanged.
+
+---
+
+## How NextHop routing works today (mechanics)
+
+Inheritance chain: `Router` → `FloodingRouter` → `NextHopRouter` → `ReliableRouter`.
+
+**The single-byte identifiers.** Both routing bytes come from one helper:
+
+```cpp
+// src/mesh/NodeDB.h:255
+uint8_t getLastByteOfNodeNum(NodeNum num) { return (uint8_t)((num & 0xFF) ? (num & 0xFF) : 0xFF); }
+```
+
+It projects a 32-bit node number onto 255 values (`0x00` is remapped to `0xFF` so it
+never collides with the `0`-valued sentinels `NO_NEXT_HOP_PREFERENCE` / `NO_RELAY_NODE`,
+`src/mesh/MeshTypes.h:44-46`). `next_hop` and `relay_node` in the packet header are
+`uint8_t` (`src/mesh/mesh.pb.h`, comments "Last byte of the node number…"). The learned
+route stored per destination, `meshtastic_NodeInfoLite::next_hop`, is also a single byte
+(`src/mesh/generated/meshtastic/deviceonly.pb.h:83`).
+
+**Sending a DM** — `NextHopRouter::send` (`src/mesh/NextHopRouter.cpp:23`):
+
+1. `p->relay_node = getLastByteOfNodeNum(getNodeNum())` (mark ourselves as relayer).
+2. `p->next_hop = getNextHop(p->to, p->relay_node)` (`src/mesh/NextHopRouter.cpp:192`):
+   look up `nodeDB->getMeshNode(to)->next_hop`; return it unless it equals the relayer
+   byte; otherwise `NO_NEXT_HOP_PREFERENCE` (→ flood).
+
+**Relaying** — `NextHopRouter::perhapsRebroadcast` (`src/mesh/NextHopRouter.cpp:133`):
+rebroadcast iff `next_hop == NO_NEXT_HOP_PREFERENCE` (flood) **or**
+`next_hop == getLastByteOfNodeNum(getNodeNum())` (we are the addressed next hop)
+(`:147`). Each node only ever compares against **its own** byte.
+
+**Learning** — `NextHopRouter::sniffReceived` (`src/mesh/NextHopRouter.cpp:89`): on an
+ACK/reply (`request_id`/`reply_id` set), if the relayer of the ACK was also a relayer of
+the original packet (validated via `PacketHistory::checkRelayers`), set
+`origTx->next_hop = p->relay_node` (`:114`). I.e. the **forward** next-hop is learned
+from the **reverse** path's relayer.
+
+**Retransmission / fallback** — `NextHopRouter::doRetransmissions`
+(`src/mesh/NextHopRouter.cpp:284`). Budgets: `NUM_RELIABLE_RETX=3` (originator: initial
+
+- 2 retries), `NUM_INTERMEDIATE_RETX=2` (relayer: 1 retry). On the **last** retry
+  (`numRetransmissions==1`) it resets `next_hop` to `NO_NEXT_HOP_PREFERENCE` on the packet
+  **and** clears `sentTo->next_hop` in NodeDB, then floods (`:313-321`). Retransmit timing
+  comes from `iface->getRetransmissionMsec`, whose contention window **grows with channel
+  utilization** (`src/mesh/RadioInterface.cpp` `getTxDelayMsec`/`getTxDelayMsecWeighted`).
+
+**Dedup / relayer history** — `PacketHistory` (`src/mesh/PacketHistory.cpp`): a bounded
+ring (`PACKETHISTORY_MAX = max(MAX_NUM_NODES*2, 100)`, 20 B/record) keyed by
+`(sender,id)`, tracking up to `NUM_RELAYERS=6` relayer **bytes** per packet in
+`relayed_by[]`. `wasRelayer` (`:490`) and `checkRelayers` (`:517`) match bytes against
+that array.
+
+---
+
+## Root-cause analysis
+
+### 1. The single byte is trusted blindly at five sites (the birthday problem)
+
+| #   | Site                             | File:line                   | Failure on collision                                                                                                      |
+| --- | -------------------------------- | --------------------------- | ------------------------------------------------------------------------------------------------------------------------- |
+| 1   | Rebroadcast self-check           | `NextHopRouter.cpp:147`     | A remote "impostor" node sharing the intended next-hop's byte also rebroadcasts → wasted airtime / congestion.            |
+| 2   | Route learning                   | `NextHopRouter.cpp:111-114` | Stores an ambiguous byte as the route; later resolves to the wrong physical node.                                         |
+| 3   | Relayer validation               | `PacketHistory.cpp:490-538` | `wasRelayer(byte)` returns true for the wrong node → mis-validated ACK / mis-learn.                                       |
+| 4   | Favorite-router hop preservation | `Router.cpp:120-145`        | **First** NodeDB node whose last byte matches wins — non-deterministic; can preserve hops for the wrong relay (hop leak). |
+| 5   | Send-path lookup                 | `NextHopRouter.cpp:192-207` | Emits a byte that may address the wrong node; no check it still maps to a reachable neighbor.                             |
+
+Collision math (uniform last byte over 255 buckets): P(collision) ≈ 50% at ~19 nodes,
+
+> 99% by ~75 nodes. Dense meshes are squarely in the "always colliding" regime.
+
+### 2. Stale routes never decay
+
+The learned `next_hop` byte is cleared only on the **current DM's** last retry
+(`NextHopRouter.cpp:313-321`). A route learned hours ago that has since gone dead is
+still trusted on the **next** DM's first attempt — which on a congested mesh is also the
+slowest attempt. Result: silent black-hole at a dead hop until the retransmission budget
+drains, then a late flood. Intermediate nodes hold stale routes indefinitely.
+
+### 3. Reverse-path (asymmetric-link) learning
+
+`origTx->next_hop` is learned from the ACK's relayer (`NextHopRouter.cpp:110-114`) — the
+**reverse** direction. RF links are frequently asymmetric, so the best reverse relay can
+be a poor forward relay. Worse, the next reverse ACK immediately re-learns the same bad
+hop, so the route **flaps** back to the bad value even after a failure reset.
+
+### 4. Congestion amplification
+
+Collision-driven impostor rebroadcasts (issue 1) add airtime; the contention window
+grows with channel utilization, so retransmit intervals **lengthen** exactly when the
+mesh is busy. The 3-try reliable budget can then expire before delivery. On dense
+meshes, efficiency _is_ reliability.
+
+### Note: pubkey-derived node numbers (develop / 2.8) — does not change the plan
+
+develop derives the node number from the public key:
+`my_node_num = crc32Buffer(public_key)` (`src/mesh/NodeDB.cpp:481`), re-derived on key
+change in `createNewIdentity()` (`src/mesh/NodeDB.cpp:3113`). This **reinforces** the
+plan rather than changing it:
+
+- **Birthday problem unchanged and now textbook-exact.** CRC32 mixes well → the last
+  byte is uniformly distributed over 256 values. Derivation adds no wire bits.
+- **Node numbers are now immutable / identity-bound.** Pre-2.8 `pickNewNodeNum()` could
+  renumber a node to dodge a conflict; now the number is fixed by the key, so a last-byte
+  collision **cannot be resolved operationally by renumbering** → M1/M2/M3 become _more_
+  necessary.
+- **Resolver gets cleaner inputs.** Stable node numbers keep a learned byte bound to one
+  identity (good for M3 freshness). `createNewIdentity()` retires the old entry by marking
+  it **ignored** and clearing its pubkey (`src/mesh/NodeDB.cpp:3123-3125`), which M1's
+  candidate gate already skips — so key rotation can't pollute resolution.
+- **No wire-free disambiguation unlocked.** A receiver still gets only 1 byte and cannot
+  recover which full node number a colliding value meant — so "detect ambiguity → flood"
+  remains the correct strategy.
+
+---
+
+## Proposed mitigations
+
+Key insight for all of M1/M2: **a 1-byte ID only needs to be unique among a node's
+direct neighbors / plausible relays, not the whole mesh.** That candidate set is small
+(typically 5–15), so a byte usually resolves unambiguously there; when it doesn't, fall
+back to the _safe_ behavior (flood / decrement / don't-learn).
+
+### M1 — Ambiguity-aware last-byte resolution (new NodeDB primitive)
+
+New types + methods in `src/mesh/NodeDB.h` (near line 255) / `src/mesh/NodeDB.cpp`
+(near `getMeshNode`, ~2936):
+
+```cpp
+enum class LastByteResolution : uint8_t { None, Unique, Ambiguous };
+struct ResolvedNode { LastByteResolution status = LastByteResolution::None; NodeNum num = 0; };
+
+// Resolve a single on-wire last-byte to a unique full NodeNum among relevant candidates.
+ResolvedNode resolveLastByte(uint8_t lastByte, bool requireDirectNeighbor);
+// Convenience: true iff exactly one relevant candidate (Ambiguous and None both -> false = SAFE).
+bool resolveUniqueLastByte(uint8_t lastByte, bool requireDirectNeighbor, NodeNum *outNum = nullptr);
+```
+
+- **One linear pass** over `meshNodes`, reusing `getNumMeshNodes()`/`getMeshNodeByIndex()`,
+  the bitfield helpers (`nodeInfoLiteIsFavorite/HasUser/IsIgnored`), `sinceLastSeen()`,
+  and `getLastByteOfNodeNum()`. **Early-exit** on the 2nd match (return `Ambiguous`).
+- **Guard:** `if (lastByte == 0) return {None, 0};` (covers `NO_RELAY_NODE` / MQTT-invalid).
+- **Candidate gate** (skip): `num == getNodeNum()` (never resolve to ourselves), `num == 0`,
+  `num == NODENUM_BROADCAST`, `nodeInfoLiteIsIgnored`. Then match
+  `getLastByteOfNodeNum(node->num) == lastByte` (cheapest test last, mirroring `Router.cpp:119`).
+- **Relevance gate:**
+  - `requireDirectNeighbor == true` (strict, for SEND): `has_hops_away && hops_away == 0`
+    **and** `sinceLastSeen(node) < NEXTHOP_NEIGHBOR_FRESH_SECS`.
+  - `requireDirectNeighbor == false` (lenient, for learn / hop-preserve): accept if direct
+    neighbor **or** `nodeInfoLiteIsFavorite` **or** role ∈ {ROUTER, ROUTER_LATE, CLIENT_BASE}.
+- **No tie-break.** A collision must return `Ambiguous` — picking "best SNR" would
+  resurrect the silent-misroute bug. (Deliberate non-goal; document in code.)
+
+New constant in `src/mesh/MeshTypes.h` (near line 44):
+`#define NEXTHOP_NEIGHBOR_FRESH_SECS (60 * 60 * 2)` (mirrors `NUM_ONLINE_SECS`).
+
+### M2 — Only route on bytes that resolve to a unique, reachable neighbor
+
+In `getNextHop` (`src/mesh/NextHopRouter.cpp:192-207`), after the existing split-horizon
+check (`node->next_hop != relay_node`), require the stored byte to resolve to a **unique,
+currently-fresh direct neighbor**; else flood:
+
+```cpp
+if (node->next_hop != relay_node) {
+    ResolvedNode r = nodeDB->resolveLastByte(node->next_hop, /*requireDirectNeighbor=*/true);
+    if (r.status == LastByteResolution::Unique) return node->next_hop;
+    LOG_WARN("Next hop 0x%x for 0x%x %s -> flood", node->next_hop, to,
+             r.status == LastByteResolution::Ambiguous ? "ambiguous among neighbors" : "no longer a neighbor");
+    return std::nullopt;
+}
+```
+
+This self-heals when a neighbor goes away (unicast-into-a-void becomes a flood). It
+applies to originating, relaying, and retrying, since all route through `getNextHop`.
+
+Apply M1's safe fallback at the other sites:
+
+- **Learning** (`NextHopRouter.cpp:111-114`): gate `origTx->next_hop = p->relay_node` on
+  `resolveUniqueLastByte(p->relay_node, /*direct=*/false)`. Ambiguous/unknown → don't
+  learn (leave route unset → flood).
+- **Favorite-router preservation** (`Router.cpp:120-145`): replace the "first match wins"
+  loop with `resolveUniqueLastByte(p->relay_node, /*direct=*/false)` + a re-check that the
+  resolved node is favorite/has_user/router. Ambiguous/none/not-favorite → **decrement**
+  (safe). Net: removes one full DB scan, adds one resolver scan (wash).
+
+**Left unchanged, by design (document why in code):**
+
+- **Site 1** rebroadcast self-check (`NextHopRouter.cpp:147`) and self-identity checks
+  (`ReliableRouter.cpp:127`): a node matches its **own** byte — no DB resolution helps. A
+  remote impostor sharing the intended next-hop's byte will still rebroadcast. M1/M2
+  shrink the blast radius by reducing how often an ambiguous byte is ever stored or
+  originated; a true fix needs a wider field (out of scope). **This is the one residual
+  the plan cannot fully close.**
+- **Site 3** `wasRelayer`/`checkRelayers` (`PacketHistory.cpp:490-538`): intentionally
+  byte-domain (both sides are on-wire bytes); the consumer (learning) is now hardened.
+  Add a one-line comment; do not change.
+
+### M3 — Route freshness / failure memory (RAM table on NextHopRouter)
+
+A bounded, LRU-evicted table keyed by destination, mirroring `PacketHistory`'s
+reuse-oldest discipline (not an unbounded map) to cap RAM.
+
+`src/mesh/NextHopRouter.h` (near `pending`, line 99):
+
+```cpp
+struct RouteHealth {
+    NodeNum dest = 0;                  // 0 == empty slot
+    uint32_t learnedAtMsec = 0;        // millis() at last (re)learn; rollover-aware
+    uint8_t consecutiveFailures = 0;
+    uint8_t lastNextHop = NO_NEXT_HOP_PREFERENCE; // byte this health refers to
+};
+static constexpr uint8_t ROUTE_HEALTH_MAX = 32;   // ~384B; drop to 16 if RAM-tight
+RouteHealth routeHealth[ROUTE_HEALTH_MAX] = {};
+// Helpers take `now` (pure/testable): findRouteHealth, getOrAllocRouteHealth,
+// noteRouteLearned, noteRouteSuccess, noteRouteFailure, isRouteStale, clearRouteHealth
+```
+
+Policy:
+
+| Constant                  | Value  | Rationale                                                                                                                                              |
+| ------------------------- | ------ | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| `ROUTE_TTL_MSEC`          | 30 min | Survives a normal conversation; re-discovers a moved node within a telemetry interval.                                                                 |
+| `ROUTE_FAILURE_THRESHOLD` | 3      | 1–2 consecutive failures are transient LoRa collisions; 3 to the same hop = dead. Accumulates **across** DMs (independent of the per-DM 3-try budget). |
+
+`isRouteStale(h, now)` = `(now - h.learnedAtMsec) >= ROUTE_TTL_MSEC || h.consecutiveFailures >= ROUTE_FAILURE_THRESHOLD`.
+All age math uses **unsigned subtraction** (rollover-safe, matching
+`PacketHistory.cpp:364`); treat `learnedAtMsec == 0` as "set now".
+
+Wiring (as built — `src/mesh/NextHopRouter.cpp`, `src/mesh/ReliableRouter.cpp`):
+
+- `getNextHop`: if a health record matches the stored byte and `isRouteStale`, clear
+  `node->next_hop` (NodeDB) **and** `clearRouteHealth`, return `nullopt` (flood). No
+  record yet (cold path, first DM after boot) → trust NodeDB, but the M2 strict-neighbor
+  gate still applies.
+- `sniffReceived` learn: gate the write through `resolveUniqueLastByte` (M2), then
+  `noteRouteLearned(p->from, p->relay_node, millis())` — resets `consecutiveFailures`
+  **only if the hop changed** (anti-flap for asymmetric re-learn); otherwise just refreshes
+  `learnedAtMsec`. (No success signal is taken on the intermediate reverse-pass: an ACK
+  merely passing through us is not proof that _we_ delivered, and resetting failures there
+  would reintroduce the asymmetric flap.)
+- `doRetransmissions`: on the last-retransmission branch (`numRetransmissions == 1`, the
+  point a directed delivery has gone un-ACKed for both originator and intermediate) →
+  `noteRouteFailure(to)`, then the existing NodeDB `next_hop` reset + flood. We deliberately
+  do **not** `clearRouteHealth` here: keeping the record is what lets the failure count
+  accumulate across DMs so a flapping reverse-path-relearned dead hop eventually ages out.
+- `ReliableRouter::sniffReceived` ACK path → `noteRouteSuccess(getFrom(p), millis())`
+  (an end-to-end ACK addressed to us is genuine forward-delivery proof; clears failures and
+  refreshes freshness). `noteRouteSuccess`/`noteRouteFailure` are no-ops when no record
+  exists, so flood-only destinations never pollute the table.
+
+**Reconciliation (no double-handling):** `doRetransmissions` owns _in-flight_ failure of
+the current DM (reset NodeDB `next_hop` + flood, and bump the cross-DM failure counter);
+`getNextHop` owns _between-DM_ staleness (TTL or failure-threshold → flood + clear). The
+only place that erases a health record is the `getNextHop` decay path; the retransmission
+path leaves it intact so the counter survives a reverse-path re-learn.
+
+### M4 — Earlier flood for unverified routes (gated, off by default)
+
+Compile-gated so healthy sparse meshes are untouched. **Default is off** — the define
+lives in `NextHopRouter.h` and must be flipped to measure:
+`#define NEXTHOP_EARLY_FLOOD_ON_UNVERIFIED 1`.
+
+In `doRetransmissions`, the directed-retry `else` branch: if the route is **not verified**
+(`!findRouteHealth(to) || consecutiveFailures > 0 || isRouteStale`), reset `next_hop` and
+flood on this attempt instead of spending another directed try. A **verified** route
+(record present, `consecutiveFailures == 0`, within TTL — i.e. recently ACKed) takes the
+unchanged directed-retry path, so the sparse-mesh happy path is untouched. Trade-off:
+airtime ↔ latency; the gate ensures we never pay the flood cost on a proven route, only on
+one we already distrust. Off by default precisely so it can be A/B-measured on the
+simulator before broad enable.
+
+---
+
+## Files to modify
+
+| File                                        | Change                                                                                                                                               |
+| ------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `src/mesh/MeshTypes.h`                      | `NEXTHOP_NEIGHBOR_FRESH_SECS`, `ROUTE_TTL_MSEC`, `ROUTE_FAILURE_THRESHOLD`, `NEXTHOP_EARLY_FLOOD_ON_UNVERIFIED`                                      |
+| `src/mesh/NodeDB.h` / `src/mesh/NodeDB.cpp` | `LastByteResolution`, `ResolvedNode`, `resolveLastByte`, `resolveUniqueLastByte`                                                                     |
+| `src/mesh/NextHopRouter.h`                  | `RouteHealth` + array + helpers; `#ifdef PIO_UNIT_TESTING public:` for helpers and `getNextHop`                                                      |
+| `src/mesh/NextHopRouter.cpp`                | `getNextHop` (M2 gate + M3 decay); `sniffReceived` (learn gate + health seed + success); `doRetransmissions` (failure counting + M4); comment site 1 |
+| `src/mesh/Router.cpp`                       | `shouldDecrementHopLimit` → resolver + favorite/router re-check                                                                                      |
+| `src/mesh/ReliableRouter.cpp`               | ACK path → `noteRouteSuccess`                                                                                                                        |
+| `test/test_nexthop_routing/test_main.cpp`   | **new** unit suite (auto-built under `[env:native]`)                                                                                                 |
+
+**Reuse, don't reinvent:** `getLastByteOfNodeNum`, `sinceLastSeen`, the bitfield helpers,
+`getMeshNodeByIndex`/`getNumMeshNodes`, PacketHistory's reuse-oldest eviction shape, and
+`MockNodeDB::addTestNode` (from `test/test_hop_scaling/test_main.cpp`).
+
+---
+
+## Edge cases
+
+- **`0x00`↔`0xFF` projection:** the resolver compares via `getLastByteOfNodeNum` on both
+  sides, so a `…00` node and a `…FF` node correctly collide on `0xFF` → `Ambiguous`. Test
+  explicitly.
+- **MQTT packets:** `relay_node`/`next_hop` are forced invalid when `hop_start == 0`
+  (`src/mesh/RadioLibInterface.cpp:603-605`) → byte 0 → resolver `None` → don't learn
+  (correct).
+- **`has_hops_away == false`** nodes are excluded from the strict gate (never fabricate a
+  Unique neighbor for M2); admitted to the lenient gate only via favorite/router role.
+  Safe; self-corrects once `hops_away` is learned.
+- **Self / broadcast:** the resolver skips `getNodeNum()` and `NODENUM_BROADCAST`;
+  `getNextHop` already early-returns for broadcast.
+- **Perf:** M2 adds one O(N) resolver scan per directed send/relay (early-exit on the 2nd
+  match), cheaper than the crypto already on that path; site-4 is a wash. If ever hot, a
+  future 256-entry last-byte index is the optimization (not now — RAM).
+
+---
+
+## Verification (all tiers)
+
+### 1. Native unit tests — new `test/test_nexthop_routing/test_main.cpp`
+
+`pio test -e native -f test_nexthop_routing`; on macOS `./bin/test-native-docker.sh -f test_nexthop_routing`.
+Design the RouteHealth helpers to take `now` as a parameter so the 30-min TTL logic is
+testable without a clock mock.
+
+- **Resolver:** None / Unique / **Ambiguous (birthday collision)** / strict-excludes-stale /
+  strict-excludes-far / lenient-includes-favorite-router / lenient-collision / skips-self /
+  skips-ignored / **`0x00`↔`0xFF` collision** / early-exit.
+- **`getNextHop`:** unique→byte, **ambiguous→nullopt**, stale-neighbor→nullopt,
+  split-horizon (relay==next_hop)→nullopt, broadcast→nullopt.
+- **RouteHealth:** TTL boundary, **rollover** (learn near `0xFFFFFFFF`, check after wrap),
+  failure threshold, success-resets, **re-learn-same-hop keeps fails (anti-flap)**,
+  re-learn-new-hop resets, LRU eviction bound, clear.
+- **Site-4:** preserve on unique favorite router; **decrement on two colliding favorites**;
+  decrement when the resolved node is not a favorite.
+- **Sparse-mesh regression:** all-distinct last bytes → every resolve Unique, `getNextHop`
+  returns the stored byte unchanged (proves no happy-path change).
+- Re-run `test_packet_history` and `test_hop_scaling` for no regression.
+
+### 2. portduino SimRadio simulator
+
+`pio run -e native && ./bin/test-simulator.sh`. Best vehicle for the **intermediate-node**
+path the 2-device bench can't reach. Line topology A — B — C: establish A→C (B learns a
+directed route), stop B relaying that dest, confirm A re-discovers via flood within
+`ROUTE_FAILURE_THRESHOLD` and that B's `noteRouteFailure`/`clearRouteHealth` fires (visible
+via the `LOG_INFO "Route to … stale"` / "Resetting next hop" lines). Use this to A/B M4
+(attempts-to-delivery, total airtime).
+
+### 3. Hardware via meshtastic MCP (auto-detect; 3+ devices for a real hop)
+
+- `mcp-server/tests/mesh/test_nexthop_multihop_recovery.py` — **the multi-hop validator
+  for this work** (added on this branch). Self-discovers an A — relay — C line, asserts a
+  directed DM is delivered across the relay (next_hop + M1/M2/M3 engaged), and asserts
+  delivery recovers after the relay is power-cycled (M3). Skips unless the bench is a true
+  multi-hop line (≥3 roles via `--hub-profile`, endpoints out of direct RF range).
+- `mcp-server/tests/mesh/test_direct_with_ack.py` — happy-path regression: a fresh/unique
+  route still delivers a want_ack DM on the first/second try (M4's gate must keep this
+  green).
+- `mcp-server/tests/mesh/test_peer_offline_recovery.py` — 2-device recovery validator: peer
+  off mid-conversation then back. Must stay green and ideally recover in fewer attempts.
+
+### 4. Build / format sanity
+
+native-macos **and** Docker both ways; trunk clang-format@16.0.3; a release `pio run` to
+confirm the `#ifdef PIO_UNIT_TESTING` visibility widening does **not** leak into
+production; sanity-check RAM headroom on the smallest nRF52 build for the ~384 B table.
+
+---
+
+## Verification status (as built on `nexthop-redux`)
+
+| Tier                             | What ran                                                                            | Result              |
+| -------------------------------- | ----------------------------------------------------------------------------------- | ------------------- |
+| Unit (native-macos)              | `test_nexthop_routing` (31 cases)                                                   | ✅ 31/31            |
+| Unit (Docker / Linux, CI parity) | `test_nexthop_routing`                                                              | ✅ 31/31            |
+| Regression                       | `test_packet_history`, `test_hop_scaling`, `test_mqtt`, `test_traffic_management`   | ✅ 105/105          |
+| Build                            | `pio run -e native-macos` (M4 off) and with `-DNEXTHOP_EARLY_FLOOD_ON_UNVERIFIED=1` | ✅ both link        |
+| Format                           | trunk `clang-format@16.0.3`                                                         | ✅ no issues        |
+| Simulator (CI `simulator-tests`) | `meshtasticd -s` + `meshtastic.test.testSimulator()` on native-macos                | ✅ exit 0, no crash |
+
+**Pending (environment-blocked, not yet run):**
+
+- **Multi-hop A–B–C recovery sim** — the `simulator/` broker hub is **not git-tracked**
+  (only stale local `.pyc`), and two `meshtasticd -s` instances can't hear each other
+  without it. The intermediate-node failure-count path and the M4 A/B therefore have unit
+  coverage of their logic but no end-to-end multi-node run yet.
+- **Hardware / multi-hop tier** — a committable bench test now exists:
+  `mcp-server/tests/mesh/test_nexthop_multihop_recovery.py`. It self-discovers a real
+  multi-hop pair (A — relay — C), asserts a directed DM is delivered across the relay, and
+  asserts delivery recovers after the relay is power-cycled (the M3 path). It
+  `pytest.skip`s cleanly unless the bench is a true line with endpoints out of direct RF
+  range (≥3 roles via `--hub-profile`), so it's safe to commit and only asserts when the
+  NextHop path is genuinely exercised. Collected + verified to skip without hardware;
+  not yet run on a bench. `test_direct_with_ack.py` / `test_peer_offline_recovery.py`
+  remain the 2-device happy-path/recovery regressions.
+
+---
+
+## Risks & limitations
+
+- **Site-1 impostor rebroadcast** is unfixable without a wider field — documented; M1/M2
+  only shrink its frequency.
+- **Dense meshes flood DMs more often** — intended (a flooded DM arrives; a mis-unicast one
+  black-holes). Call out in the PR so reviewers expect a slightly higher DM flood rate on
+  very dense meshes.
+- **M4 airtime** if the gate is too loose → default conservative + compile-gated +
+  simulator A/B before broad enable.
+- **RAM** ~384 B (32 slots); 16 slots (~192 B) with graceful LRU degradation if tight.
+- **Asymmetric flap** not fully closed (a _new_ bad hop resets the counter); the TTL
+  backstop bounds it. Per-hop failure history is future work (more RAM).
+
+---
+
+## How to continue this work (commit sequencing)
+
+Each step is independently testable; land them as separate commits.
+
+1. **M1 resolver + unit tests** — `NodeDB` only; no behavior change until wired. Lands the
+   `resolveLastByte`/`resolveUniqueLastByte` primitive and its full unit-test matrix.
+2. **M2 + wiring + tests** — `getNextHop` strict gate, learning gate, favorite-router
+   preservation rewrite. Adds the `getNextHop` and site-4 tests.
+3. **M3 health table + decay + tests** — RAM `RouteHealth` table, decay-on-read, failure/
+   success accounting, reconciliation with the existing last-retry reset. Adds the
+   route-health unit tests and the simulator recovery check.
+4. **M4 gated tuning** — early-flood-on-unverified behind the compile flag; simulator A/B
+   and hardware regression.
+
+Reference plan (with the same content) was developed at
+`~/.claude/plans/nexthop-routing-for-direct-lexical-shell.md` on the author's machine; this
+in-repo doc is the canonical handoff copy.

extra_scripts/nrf52_lto.py

@@ -0,0 +1,148 @@
+#!/usr/bin/env python3
+# trunk-ignore-all(ruff/F821)
+# trunk-ignore-all(flake8/F821)
+#
+# Whole-image LTO for nrf52840 (~-60KB; ~-23KB beyond src-only LTO), EXCEPT the objects
+# that own interrupt/exception handlers.
+#
+# Every ISR is referenced only from the assembly vector table (gcc_startup_nrf52840.S),
+# which LTO cannot see -> whole-program LTO judges the handlers dead, removes them, and
+# the weak `b .` Default_Handler stubs prevail -> the IRQ lands in an infinite loop and the
+# chip hangs (or the peripheral silently stalls). Compiling the handler-bearing objects
+# WITHOUT LTO lets ordinary linking keep the strong handlers; everything else stays LTO'd:
+#   - framework core (/FrameworkArduino/, /cores/nRF5/): every nrfx ISR + the FreeRTOS
+#     SVC/PendSV port.
+#   - TinyUSB nrf port (Adafruit_TinyUSB_nrf.cpp): USBD_IRQHandler (USB data path).
+#   - library .cpp files that own a vector ISR (would otherwise be silently dropped):
+#       bluefruit.cpp     -> SD_EVT/SWI2_EGU2  (SoftDevice BLE-event delivery -- advertising
+#                            hangs without it)
+#       Wire_nRF52.cpp    -> SPIM0/TWIM0 + SPIM1/TWIM1 (interrupt-driven I2C/SPI)
+#       PDM.cpp           -> PDM_IRQHandler   (PDM microphone)
+#       RotaryEncoder.cpp -> QDEC_IRQHandler  (hardware quadrature/rotary encoder)
+#
+# A post-link guard (bottom of this file) fails the build if a critical handler was dropped
+# anyway -- so a future deps bump or a new ISR-owning library becomes a red build, not a field
+# hang. To hunt a dropped ISR by hand: nm the .elf for `_IRQHandler$` symbols marked `W`, then
+# grep the libs/framework for who defines them.
+#
+# HW-validated: RAK4631 (SX1262) + muzi-base (LR1121).
+import glob
+import os
+
+Import("env")
+
+env.Append(LINKFLAGS=["-flto", "-flto-partition=1to1"])
+
+# The -fno-lto re-compiles below run with the global env, which lacks the framework's
+# bundled-library include dirs -- and those libs cross-include each other (Wire pulls in
+# Adafruit_TinyUSB.h, which pulls in SPI.h, ...). Add every bundled-lib dir (+ its src/) so
+# the re-compiles resolve without chasing headers one at a time.
+_fw = env.PioPlatform().get_package_dir("framework-arduinoadafruitnrf52") or ""
+_extra_inc = []
+for _d in sorted(glob.glob(os.path.join(_fw, "libraries", "*"))):
+    if os.path.isdir(_d):
+        _extra_inc.append(_d)
+        if os.path.isdir(os.path.join(_d, "src")):
+            _extra_inc.append(os.path.join(_d, "src"))
+
+FRAMEWORK = ("/FrameworkArduino/", "/cores/nRF5/")
+USB_ISR = "Adafruit_TinyUSB_nrf"  # USBD_IRQHandler
+# Library .cpp files that define vector-table ISRs (the rest of their lib stays LTO'd):
+LIB_ISR = ("/bluefruit.cpp", "/Wire_nRF52.cpp", "/PDM.cpp", "/RotaryEncoder.cpp")
+
+
+def _no_lto(node):
+    try:
+        path = node.get_abspath()
+    except Exception:
+        path = str(node)
+    path = path.replace(
+        "\\", "/"
+    )  # normalize Windows backslashes so matches work cross-platform
+    if (
+        USB_ISR in path
+        or any(s in path for s in FRAMEWORK)
+        or any(s in path for s in LIB_ISR)
+    ):
+        return env.Object(
+            node,
+            CCFLAGS=env["CCFLAGS"] + ["-fno-lto"],
+            CPPPATH=env["CPPPATH"] + _extra_inc,
+        )
+    return node
+
+
+env.AddBuildMiddleware(_no_lto)
+
+
+# --- post-link guard: catch a dropped ISR handler at build time (CI footgun protection) ----
+# After every link, fail the build if one of these critical vector-table handlers resolved to
+# the weak `b .` Default_Handler stub -- i.e. LTO (or a deps bump, or a new ISR-owning library
+# that nobody added to LIB_ISR) silently dropped it. A dropped handler hangs the chip the
+# instant that IRQ fires; this turns a field hang into a red build. CI builds every nrf52840
+# target, so this runs on every PR automatically. If a board deliberately stops using one of
+# these, edit the tuples on purpose.
+_REQUIRED_STRONG = (
+    "SWI2_EGU2_IRQHandler",  # SoftDevice BLE event (SD_EVT) -- advertising & connections
+    "GPIOTE_IRQHandler",  # GPIO interrupts: radio DIO + buttons
+    "RTC1_IRQHandler",  # FreeRTOS scheduler tick
+)
+# Owned by the TinyUSB stack, so only required when the board builds with USB at all.
+# Boards without native USB wiring (e.g. wio-sdk-wm1110's CH340 UART) strip TinyUSB via
+# disable_adafruit_usb.py / unflagging USE_TINYUSB, leaving these legitimately weak.
+_REQUIRED_STRONG_USB = (
+    "USBD_IRQHandler",  # USB CDC (serial console + 1200bps DFU trigger)
+    "POWER_CLOCK_IRQHandler",  # USB power events (VBUS detect/ready) via TinyUSB hal
+)
+
+_tc = env.PioPlatform().get_package_dir("toolchain-gccarmnoneeabi") or ""
+_NM = os.path.join(_tc, "bin", "arm-none-eabi-nm")
+if not os.path.isfile(_NM):
+    _NM = "arm-none-eabi-nm"  # fall back to PATH
+
+
+def _assert_isr_handlers_survived(source, target, env):
+    import subprocess
+    import sys
+
+    try:
+        # Resolve the ELF at build time; target[0] is the buildprog alias, not the file.
+        elf = env.subst("$BUILD_DIR/${PROGNAME}.elf")
+        out = subprocess.check_output([_NM, elf], universal_newlines=True)
+    except Exception as exc:  # tooling hiccup: warn loudly, don't wedge the build
+        print("nrf52_lto: WARNING - ISR-handler guard skipped (nm failed: %s)" % exc)
+        return
+    # nm line: "<addr> <type> <symbol>". type 'T'/'t' = strong (good); 'W'/'w' = weak stub.
+    kind = {}
+    for line in out.split("\n"):
+        f = line.split()
+        if len(f) >= 3 and f[-1].endswith("_IRQHandler"):
+            kind[f[-1]] = f[-2]
+    required = list(_REQUIRED_STRONG)
+    defines = [
+        str(d[0] if isinstance(d, tuple) else d) for d in env.get("CPPDEFINES", [])
+    ]
+    if "USE_TINYUSB" in defines:
+        required += _REQUIRED_STRONG_USB
+    dropped = [h for h in required if kind.get(h, "W").upper() != "T"]
+    if dropped:
+        sys.stderr.write(
+            "\n*** nrf52 LTO guard: interrupt handler(s) DROPPED: %s ***\n"
+            "Each resolved to the weak Default_Handler stub, so the chip hangs when that IRQ\n"
+            "fires. Compile the .cpp that defines the handler with -fno-lto by adding it to\n"
+            "LIB_ISR in extra_scripts/nrf52_lto.py. Find the owner of FOO_IRQHandler with:\n"
+            "  grep -rl FOO_IRQHandler <framework-arduinoadafruitnrf52>/{libraries,cores}\n\n"
+            % ", ".join(dropped)
+        )
+        from SCons.Script import Exit
+
+        Exit(1)  # canonical SCons build-abort -> red build
+    print(
+        "nrf52_lto: ISR-handler guard OK -- %d critical handlers strong" % len(required)
+    )
+
+
+# Attach to the phony "buildprog" alias, NOT the .elf file node: SCons can skip a post-action
+# on a file target during an incremental relink (observed), but the buildprog alias runs every
+# build -- so the guard fires on local incremental rebuilds and clean CI builds alike.
+env.AddPostAction("buildprog", _assert_isr_handlers_survived)

extra_scripts/nrf52_warm_region.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+# trunk-ignore-all(ruff/F821)
+# trunk-ignore-all(flake8/F821): For SConstruct imports
+#
+# Post-link guard for the warm-node-store raw-flash region on nRF52840.
+#
+# The 3 app-region pages below LittleFS (0xEA000-0xED000, reclaimed by whole-image
+# LTO) are reserved for the WarmNodeStore record-ring (see WarmNodeStore.h). Our
+# linker scripts (nrf52840_s140_v6.ld and nrf52840_s140_v7.ld) cap the image at
+# 0xEA000, but boards on the framework-default script (FLASH ending at 0xED000) could
+# silently place code in those pages — the first warm-store save would then brick the
+# device. This turns that into a build failure.
+#
+# Image flash end = __etext + sizeof(.data) (loaded at LMA __etext); symbols from
+# the framework's nrf52_common.ld.
+import os
+
+Import("env")
+
+WARM_REGION_BASE = 0xEA000  # keep in sync with WARM_FLASH_REGION_BASE in WarmNodeStore.h (3 x 4 KB record-ring)
+
+_tc = env.PioPlatform().get_package_dir("toolchain-gccarmnoneeabi") or ""
+_NM = os.path.join(_tc, "bin", "arm-none-eabi-nm")
+if not os.path.isfile(_NM):
+    _NM = "arm-none-eabi-nm"  # fall back to PATH
+
+
+def _assert_warm_region_clear(source, target, env):
+    import subprocess
+    import sys
+
+    try:
+        elf = env.subst("$BUILD_DIR/${PROGNAME}.elf")
+        out = subprocess.check_output([_NM, elf], universal_newlines=True)
+    except Exception as exc:  # tooling hiccup: warn loudly, don't wedge the build
+        print("nrf52_warm_region: WARNING - guard skipped (nm failed: %s)" % exc)
+        return
+
+    syms = {}
+    for line in out.split("\n"):
+        f = line.split()
+        if len(f) >= 3 and f[-1] in ("__etext", "__data_start__", "__data_end__"):
+            syms[f[-1]] = int(f[0], 16)
+    if len(syms) != 3:
+        print("nrf52_warm_region: WARNING - guard skipped (linker symbols not found)")
+        return
+
+    flash_end = syms["__etext"] + (syms["__data_end__"] - syms["__data_start__"])
+    if flash_end > WARM_REGION_BASE:
+        sys.stderr.write(
+            "\n*** nrf52 warm-region guard: image ends at 0x%X, past the reserved "
+            "warm-store region at 0x%X ***\n"
+            "The 12 KB region at 0xEA000 holds the WarmNodeStore record-ring; a warm-store\n"
+            "save would overwrite this firmware's tail. Shrink the image, or shrink/move\n"
+            "the region (WARM_FLASH_REGION_BASE in src/mesh/WarmNodeStore.h, the FLASH\n"
+            "LENGTH in src/platform/nrf52/nrf52840_s140_v6.ld and _v7.ld, and this guard).\n\n"
+            % (flash_end, WARM_REGION_BASE)
+        )
+        from SCons.Script import Exit
+
+        Exit(1)
+    print(
+        "nrf52_warm_region: guard OK -- image ends at 0x%X, %d KB clear of the warm region"
+        % (flash_end, (WARM_REGION_BASE - flash_end) // 1024)
+    )
+
+
+# Attach to the phony "buildprog" alias (not the .elf node) so the guard runs
+# on incremental relinks too -- same reasoning as nrf52_lto.py's guard.
+env.AddPostAction("buildprog", _assert_warm_region_clear)

mcp-server/tests/mesh/test_nexthop_multihop_recovery.py

@@ -0,0 +1,347 @@
+"""Multi-hop NextHop directed-message delivery + relay-recovery (bench test).
+
+This is the hardware/tier-3 validator for the NextHop DM reliability work
+(see `docs/nexthop-routing-reliability.md`). The unit suite
+`test/test_nexthop_routing` covers the routing *logic* exhaustively; this test
+covers the *end-to-end* multi-hop behavior that only a real (or RF-separated)
+mesh exercises:
+
+  * a directed DM that must traverse a relay is delivered (next_hop routing +
+    the M1/M2 ambiguity gate + M3 route learning all engage), and
+  * when the established relay drops and returns, delivery recovers rather than
+    black-holing (the M3 stale-route decay / re-learn path).
+
+TOPOLOGY REQUIREMENT — why this usually SKIPS:
+  A NextHop relay only happens when the two endpoints are NOT direct neighbors.
+  Three co-located radios all hear each other, so A→C is a single direct hop and
+  next_hop never engages. To run this test the bench must be a *line* — A — B — C
+  — with the endpoints out of each other's direct RF range (physical distance or
+  attenuators). The `multihop_topology` fixture detects this automatically: it
+  warms the mesh, looks for a pair that is ≥1 hop apart, confirms the relay via
+  traceroute, and `pytest.skip`s cleanly when the bench is all-direct. So this
+  file is safe to commit and run anywhere — it only *asserts* when the topology
+  genuinely requires a relay.
+
+REQUIREMENTS:
+  * ≥3 baked devices. The default hub profile is 2 roles (nrf52, esp32s3); add a
+    third via `--hub-profile=path/to/hub.yaml` (see conftest `hub_profile`).
+  * The relay-recovery test additionally needs uhubctl + a power-controllable
+    relay port (same gate the other power tests use).
+"""
+
+from __future__ import annotations
+
+import time
+from typing import Any
+
+import pytest
+from meshtastic_mcp.connection import connect
+from tests import _power
+from tests._port_discovery import resolve_port_by_role
+
+from ._receive import ReceiveCollector, nudge_nodeinfo, nudge_nodeinfo_port
+
+
+def _hops_away(rec: dict[str, Any]) -> int | None:
+    """Read a node's hop distance from a `nodesByNum` entry, tolerating either
+    the camelCase (`hopsAway`) or snake_case (`hops_away`) spelling depending on
+    the meshtastic-python version."""
+    for key in ("hopsAway", "hops_away"):
+        val = rec.get(key)
+        if isinstance(val, int):
+            return val
+    return None
+
+
+def _warm_mesh(ports: list[str], rounds: int = 2, settle: float = 6.0) -> None:
+    """Flood a fresh NodeInfo from every node so the whole mesh (including
+    multi-hop pairs, reached via relayed broadcasts) populates pubkeys and hop
+    distances. Best-effort — a single node failing to nudge shouldn't abort."""
+    for _ in range(rounds):
+        for port in ports:
+            try:
+                nudge_nodeinfo_port(port)
+            except Exception:  # noqa: BLE001 — warmup is best-effort
+                pass
+            time.sleep(0.5)
+        time.sleep(settle)
+
+
+def _wait_for_pubkey(
+    tx_iface: Any, rx_num: int, rx_port: str, deadline_s: float = 90.0
+) -> bool:
+    """Block until `tx_iface` holds `rx_num`'s public key (directed PKI sends
+    NAK without it). Re-nudges both sides periodically; multi-hop warmup is
+    slower than the 2-device case because NodeInfo must be relayed, hence the
+    longer default deadline."""
+    deadline = time.monotonic() + deadline_s
+    last_nudge = time.monotonic()
+    while time.monotonic() < deadline:
+        rec = (tx_iface.nodesByNum or {}).get(rx_num, {})
+        if rec.get("user", {}).get("publicKey"):
+            return True
+        if time.monotonic() - last_nudge > 20.0:
+            nudge_nodeinfo_port(rx_port)
+            nudge_nodeinfo(tx_iface)
+            last_nudge = time.monotonic()
+        time.sleep(1.0)
+    return False
+
+
+def _traceroute_route(tx_port: str, rx_num: int, rx_port: str) -> list[int] | None:
+    """Run a traceroute TX→RX and return the forward `route` (list of relay node
+    numbers), or None if it couldn't be obtained. Mirrors test_traceroute's
+    request/PKI/retry pattern."""
+    from meshtastic.mesh_interface import MeshInterface
+
+    with ReceiveCollector(tx_port, topic="meshtastic.receive.traceroute") as tx:
+        nudge_nodeinfo_port(rx_port)
+        tx.broadcast_nodeinfo_ping()
+        if not _wait_for_pubkey(tx._iface, rx_num, rx_port, 60.0):
+            return None
+        for _attempt in range(2):
+            try:
+                tx._iface.sendTraceRoute(dest=rx_num, hopLimit=5)
+                break
+            except MeshInterface.MeshInterfaceError:
+                time.sleep(5.0)
+        else:
+            return None
+        pkt = tx.wait_for(lambda p: p.get("from") == rx_num, timeout=8.0)
+        if pkt is None:
+            return None
+        tr = (pkt.get("decoded", {}) or {}).get("traceroute") or {}
+        return [int(n) for n in (tr.get("route") or [])]
+
+
+@pytest.fixture(scope="session")
+def multihop_topology(baked_mesh: dict[str, Any]) -> dict[str, Any]:
+    """Discover a real multi-hop pier (tx → relay → rx) on the bench, or skip.
+
+    Returns {tx_role, tx_port, rx_role, rx_port, rx_num, relay_role, relay_num}.
+    """
+    roles = sorted(baked_mesh)
+    if len(roles) < 3:
+        pytest.skip(
+            "multi-hop NextHop test needs ≥3 baked devices arranged as a line "
+            "(endpoints out of direct RF range). Add a third role via "
+            f"--hub-profile. Detected roles: {roles}"
+        )
+
+    by_role = {r: (baked_mesh[r]["port"], baked_mesh[r]["my_node_num"]) for r in roles}
+    if any(num is None for _, num in by_role.values()):
+        pytest.skip("a baked device is missing my_node_num; can't map the topology")
+
+    _warm_mesh([port for port, _ in by_role.values()])
+
+    # Find an ordered pair that is ≥1 hop apart, using each node's own nodeDB
+    # (cheap — no traceroute yet). On an all-direct bench nothing qualifies.
+    multihop_pair: tuple[str, str] | None = None
+    for a_role in roles:
+        a_port, _ = by_role[a_role]
+        try:
+            with connect(port=a_port) as a_iface:
+                nodes = a_iface.nodesByNum or {}
+        except Exception:  # noqa: BLE001
+            continue
+        for c_role in roles:
+            if c_role == a_role:
+                continue
+            _, c_num = by_role[c_role]
+            hops = _hops_away(nodes.get(c_num, {}))
+            if hops is not None and hops >= 1:
+                multihop_pair = (a_role, c_role)
+                break
+        if multihop_pair:
+            break
+
+    if not multihop_pair:
+        pytest.skip(
+            "no multi-hop pair found — every device appears to be a direct "
+            "neighbor. Arrange the bench as a line (A — B — C) with the "
+            "endpoints out of direct RF range (distance or attenuators) so a "
+            "relay is actually required, then re-run."
+        )
+
+    a_role, c_role = multihop_pair
+    a_port, _ = by_role[a_role]
+    c_port, c_num = by_role[c_role]
+
+    route = _traceroute_route(a_port, c_num, c_port)
+    if not route:
+        pytest.skip(
+            f"{a_role}→{c_role} looked multi-hop but traceroute returned no "
+            "intermediate relay; can't identify the relay node to drive the "
+            "recovery test"
+        )
+
+    relay_num = route[0]
+    relay_role = next((r for r in roles if by_role[r][1] == relay_num), None)
+    return {
+        "tx_role": a_role,
+        "tx_port": a_port,
+        "rx_role": c_role,
+        "rx_port": c_port,
+        "rx_num": c_num,
+        "relay_role": relay_role,
+        "relay_num": relay_num,
+    }
+
+
+@pytest.mark.timeout(300)
+def test_multihop_dm_delivers(multihop_topology: dict[str, Any]) -> None:
+    """A directed wantAck DM that must traverse the relay is delivered.
+
+    Exercises the NextHop routing path end-to-end: TX picks a next hop toward
+    RX (M2 gate), the relay resolves the next_hop byte and forwards (M1), and
+    the route is learned from the returning ACK (M3). Retries absorb transient
+    LoRa loss; the assertion is on eventual delivery.
+    """
+    tx_port = multihop_topology["tx_port"]
+    rx_port = multihop_topology["rx_port"]
+    rx_num = multihop_topology["rx_num"]
+    tx_role = multihop_topology["tx_role"]
+    rx_role = multihop_topology["rx_role"]
+    relay_role = multihop_topology["relay_role"]
+
+    unique = f"nexthop-mh-{tx_role}-to-{rx_role}-{int(time.time())}"
+
+    with ReceiveCollector(rx_port, topic="meshtastic.receive.text") as rx:
+        rx.broadcast_nodeinfo_ping()
+        with connect(port=tx_port) as tx_iface:
+            nudge_nodeinfo(tx_iface)
+            if not _wait_for_pubkey(tx_iface, rx_num, rx_port, 90.0):
+                pytest.skip(
+                    f"{tx_role} never learned {rx_role}'s pubkey over the relay; "
+                    "multi-hop PKI warmup didn't complete"
+                )
+            got = None
+            for _attempt in range(3):
+                pkt = tx_iface.sendText(unique, destinationId=rx_num, wantAck=True)
+                assert pkt is not None
+                got = rx.wait_for(
+                    lambda p: p.get("decoded", {}).get("text") == unique,
+                    timeout=45,
+                )
+                if got is not None:
+                    break
+                rx.broadcast_nodeinfo_ping()
+                nudge_nodeinfo(tx_iface)
+                time.sleep(5.0)
+
+    assert got is not None, (
+        f"multi-hop directed DM {tx_role}→{rx_role} via relay "
+        f"{relay_role!r} never landed — NextHop multi-hop delivery is broken"
+    )
+
+
+@pytest.mark.timeout(600)
+def test_multihop_relay_recovery(
+    multihop_topology: dict[str, Any],
+    power_cycle,  # noqa: ARG001 — forces the uhubctl-availability skip
+) -> None:
+    """Delivery recovers after the established relay drops and returns.
+
+    Establishes a baseline DM (route via relay learned), powers the relay OFF
+    (confirming TX survives sending across a downed relay), then powers it back
+    ON and asserts directed delivery resumes — the M3 stale-route decay /
+    re-learn path. With a strict A — B — C line there is no path while B is down,
+    so we only assert TX doesn't crash during the outage; the delivery assertion
+    is after B returns.
+    """
+    relay_role = multihop_topology["relay_role"]
+    if not relay_role:
+        pytest.skip(
+            "relay node isn't one of the baked hub roles, so it can't be "
+            "power-cycled; recovery test needs a controllable relay"
+        )
+
+    tx_port = multihop_topology["tx_port"]
+    rx_port = multihop_topology["rx_port"]
+    rx_num = multihop_topology["rx_num"]
+    tx_role = multihop_topology["tx_role"]
+    rx_role = multihop_topology["rx_role"]
+
+    base = f"mh-recover-base-{int(time.time())}"
+    post = f"mh-recover-post-{int(time.time())}"
+
+    # Baseline: confirm delivery works (so the route via the relay is learned)
+    # before we perturb anything — otherwise a later failure is ambiguous.
+    with ReceiveCollector(rx_port, topic="meshtastic.receive.text") as rx:
+        rx.broadcast_nodeinfo_ping()
+        with connect(port=tx_port) as tx_iface:
+            nudge_nodeinfo(tx_iface)
+            if not _wait_for_pubkey(tx_iface, rx_num, rx_port, 90.0):
+                pytest.skip("multi-hop PKI warmup failed; can't run recovery test")
+            tx_iface.sendText(base, destinationId=rx_num, wantAck=True)
+            assert (
+                rx.wait_for(
+                    lambda p: p.get("decoded", {}).get("text") == base, timeout=45
+                )
+                is not None
+            ), "baseline multi-hop delivery failed — skipping recovery to avoid a false result"
+
+    # Power the relay OFF.
+    try:
+        _power.power_off(relay_role)
+        _power.wait_for_absence(relay_role, timeout_s=15.0)
+    except Exception as exc:  # noqa: BLE001
+        try:
+            _power.power_on(relay_role)
+            resolve_port_by_role(relay_role, timeout_s=30.0)
+        except Exception:  # noqa: BLE001
+            pass
+        pytest.skip(f"can't power-control relay {relay_role!r}: {exc}")
+
+    # With the only relay down there's no path; we just confirm TX accepts the
+    # send and survives its internal retries (it must not crash / wedge).
+    try:
+        with connect(port=tx_port) as tx_iface:
+            pkt = tx_iface.sendText(
+                f"mh-while-down-{int(time.time())}",
+                destinationId=rx_num,
+                wantAck=True,
+            )
+            assert pkt is not None
+            time.sleep(8.0)  # let retransmissions + route decay run
+    except Exception as exc:  # noqa: BLE001 — restore bench state before failing
+        _power.power_on(relay_role)
+        resolve_port_by_role(relay_role, timeout_s=30.0)
+        raise AssertionError(
+            f"TX crashed sending across a downed relay: {exc}"
+        ) from exc
+
+    # Power the relay back ON and let it re-enumerate + boot.
+    _power.power_on(relay_role)
+    time.sleep(0.5)
+    try:
+        resolve_port_by_role(relay_role, timeout_s=30.0)
+    except Exception:  # noqa: BLE001 — relay port isn't one we connect to directly
+        pass
+    time.sleep(8.0)
+    _warm_mesh([tx_port, rx_port], rounds=1)  # re-flood so the relay re-learns
+
+    # Delivery should resume once the relay is back (M3 re-learn / decay path).
+    got = None
+    with ReceiveCollector(rx_port, topic="meshtastic.receive.text") as rx:
+        rx.broadcast_nodeinfo_ping()
+        with connect(port=tx_port) as tx_iface:
+            nudge_nodeinfo(tx_iface)
+            _wait_for_pubkey(tx_iface, rx_num, rx_port, 90.0)
+            for _attempt in range(4):
+                pkt = tx_iface.sendText(post, destinationId=rx_num, wantAck=True)
+                assert pkt is not None
+                got = rx.wait_for(
+                    lambda p: p.get("decoded", {}).get("text") == post,
+                    timeout=45,
+                )
+                if got is not None:
+                    break
+                rx.broadcast_nodeinfo_ping()
+                nudge_nodeinfo(tx_iface)
+                time.sleep(6.0)
+
+    assert got is not None, (
+        f"after relay {relay_role!r} returned, multi-hop DM {tx_role}→{rx_role} "
+        "never resumed — stale-route recovery (M3) may be broken"
+    )

mcp-server/tests/test_00_bake.py

@@ -44,7 +44,7 @@ _ESP32_ARCHES = {
     "esp32-c6",
     "esp32c6",
 }
-_NRF52_ARCHES = {"nrf52", "nrf52840", "nrf52832"}
+_NRF52_ARCHES = {"nrf52", "nrf52840"}
 
 
 def _wait_port_free(port: str, *, timeout_s: float = 15.0, role: str = "") -> None:

platformio.ini

@@ -103,7 +103,7 @@ build_unflags =
 	-std=gnu++11
 build_flags = ${env.build_flags} -Os
 	-std=gnu++17
-build_src_filter = ${env.build_src_filter} -<platform/portduino/> -<graphics/niche/>
+build_src_filter = ${env.build_src_filter} -<platform/> +<platform/extra_variants/> -<graphics/niche/>
 
 ; Common libs for communicating over TCP/IP networks such as MQTT
 [networking_base]
@@ -200,6 +200,16 @@ lib_deps =
 	https://github.com/adafruit/Adafruit_TSL2561/archive/refs/tags/1.1.3.zip
 	# renovate: datasource=github-tags depName=BH1750_WE packageName=wollewald/BH1750_WE
 	https://github.com/wollewald/BH1750_WE/archive/refs/tags/1.1.10.zip
+	# renovate: datasource=github-tags depName=Sensirion Core packageName=sensirion/arduino-core
+	https://github.com/Sensirion/arduino-core/archive/refs/tags/0.7.3.zip
+	# renovate: datasource=github-tags depName=Sensirion I2C SCD4x packageName=sensirion/arduino-i2c-scd4x
+	https://github.com/Sensirion/arduino-i2c-scd4x/archive/refs/tags/1.1.0.zip
+	# renovate: datasource=github-tags depName=Sensirion I2C SFA3x packageName=sensirion/arduino-i2c-sfa3x
+	https://github.com/Sensirion/arduino-i2c-sfa3x/archive/refs/tags/1.0.0.zip
+	# renovate: datasource=github-tags depName=Sensirion I2C SCD30 packageName=sensirion/arduino-i2c-scd30
+	https://github.com/Sensirion/arduino-i2c-scd30/archive/refs/tags/1.0.0.zip
+	# renovate: datasource=github-tags depName=arduino-sht packageName=sensirion/arduino-sht
+	https://github.com/Sensirion/arduino-sht/archive/refs/tags/v1.2.6.zip
 
 ; Common environmental sensor libraries (not included in native / portduino)
 [environmental_extra_common]
@@ -218,16 +228,6 @@ lib_deps =
 	closedcube/ClosedCube OPT3001@1.1.2
 	# renovate: datasource=git-refs depName=meshtastic-DFRobot_LarkWeatherStation packageName=https://github.com/meshtastic/DFRobot_LarkWeatherStation gitBranch=master
 	https://github.com/meshtastic/DFRobot_LarkWeatherStation/archive/4de3a9cadef0f6a5220a8a906cf9775b02b0040d.zip
-	# renovate: datasource=github-tags depName=Sensirion Core packageName=sensirion/arduino-core
-	https://github.com/Sensirion/arduino-core/archive/refs/tags/0.7.3.zip
-	# renovate: datasource=github-tags depName=Sensirion I2C SCD4x packageName=sensirion/arduino-i2c-scd4x
-	https://github.com/Sensirion/arduino-i2c-scd4x/archive/refs/tags/1.1.0.zip
-	# renovate: datasource=github-tags depName=Sensirion I2C SFA3x packageName=sensirion/arduino-i2c-sfa3x
-	https://github.com/Sensirion/arduino-i2c-sfa3x/archive/refs/tags/1.0.0.zip
-	# renovate: datasource=github-tags depName=Sensirion I2C SCD30 packageName=sensirion/arduino-i2c-scd30
-	https://github.com/Sensirion/arduino-i2c-scd30/archive/refs/tags/1.0.0.zip
-	# renovate: datasource=github-tags depName=arduino-sht packageName=sensirion/arduino-sht
-	https://github.com/Sensirion/arduino-sht/archive/refs/tags/v1.2.6.zip
 
 ; Environmental sensors with BSEC2 (Bosch proprietary IAQ)
 [environmental_extra]

src/FSCommon.h

@@ -14,8 +14,8 @@
 #define FILE_O_READ "r"
 #endif
 
-#if defined(ARCH_STM32WL)
-// STM32WL
+#if defined(ARCH_STM32)
+// STM32
 #include "LittleFS.h"
 #define FSCom InternalFS
 #define FSBegin() FSCom.begin()

src/MessageStore.cpp

@@ -1,5 +1,5 @@
 #include "configuration.h"
-#if HAS_SCREEN
+#if HAS_SCREEN || defined(MESHTASTIC_INCLUDE_NICHE_GRAPHICS)
 #include "FSCommon.h"
 #include "MessageStore.h"
 #include "NodeDB.h"
@@ -354,6 +354,7 @@ void MessageStore::clearAllMessages()
     resetMessagePool();
 
 #ifdef FSCom
+    concurrency::LockGuard guard(spiLock);
     SafeFile f(filename.c_str(), false);
     uint8_t count = 0;
     f.write(&count, 1); // write "0 messages"

src/MessageStore.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#if HAS_SCREEN
+#if HAS_SCREEN || defined(MESHTASTIC_INCLUDE_NICHE_GRAPHICS)
 
 // Disable debug logging entirely on release builds of HELTEC_MESH_SOLAR for space constraints
 #if defined(HELTEC_MESH_SOLAR)

src/Power.cpp

@@ -14,6 +14,7 @@
  * For more information, see: https://meshtastic.org/
  */
 #include "power.h"
+#include "BluetoothCommon.h"
 #include "MessageStore.h"
 #include "NodeDB.h"
 #include "PowerFSM.h"
@@ -47,7 +48,7 @@
 #include "concurrency/LockGuard.h"
 #endif
 
-#if defined(ARCH_STM32WL) && defined(BATTERY_PIN)
+#if defined(ARCH_STM32) && defined(BATTERY_PIN)
 #include "stm32yyxx_ll_adc.h"
 
 /* Analog read resolution */
@@ -430,7 +431,7 @@ class AnalogBatteryLevel : public HasBatteryLevel
             float scaled = 0;
 
             battery_adcEnable();
-#ifdef ARCH_STM32WL
+#ifdef ARCH_STM32
             // STM32 ADC with VREFINT runtime calibration
             Vref = __LL_ADC_CALC_VREFANALOG_VOLTAGE(analogRead(AVREF), LL_ADC_RESOLUTION);
             raw = analogRead(BATTERY_PIN);
@@ -607,7 +608,7 @@ class AnalogBatteryLevel : public HasBatteryLevel
     bool initial_read_done = false;
     float last_read_value = (OCV[NUM_OCV_POINTS - 1] * NUM_CELLS);
     uint32_t last_read_time_ms = 0;
-#ifdef ARCH_STM32WL
+#ifdef ARCH_STM32
     // 3300mV placeholder for STM32 errata where VREFINT factory calibration may be missing
     // (e.g. STM32U0, see DS14756 Rev 3 §2.4.1 "VREFINT offset")
     uint32_t Vref = 3300;
@@ -717,7 +718,7 @@ bool Power::analogInit()
 #define BATTERY_SENSE_RESOLUTION_BITS 10
 #endif
 
-#ifdef ARCH_STM32WL
+#ifdef ARCH_STM32
     analogReadResolution(BATTERY_SENSE_RESOLUTION_BITS);
 #elif defined(ARCH_ESP32) // ESP32 needs special analog stuff
     adc_oneshot_unit_init_cfg_t init_config = {
@@ -748,7 +749,7 @@ bool Power::analogInit()
 
     // NRF52 ADC init moved to powerHAL_init in nrf52 platform
 
-#if !defined(ARCH_ESP32) && !defined(ARCH_STM32WL)
+#if !defined(ARCH_ESP32) && !defined(ARCH_STM32)
     analogReadResolution(BATTERY_SENSE_RESOLUTION_BITS);
 #endif
 
@@ -837,7 +838,7 @@ void Power::reboot()
     }
     LOG_DEBUG("final reboot!");
     ::reboot();
-#elif defined(ARCH_STM32WL)
+#elif defined(ARCH_STM32)
     HAL_NVIC_SystemReset();
 #else
     rebootAtMsec = -1;
@@ -962,6 +963,10 @@ void Power::readPowerStatus()
         lastLogTime = millis();
     }
     newStatus.notifyObservers(&powerStatus2);
+
+    // Mirror battery level to the BLE Battery Service (0x2A19); the platform layer clamps and dedupes.
+    if (hasBattery == OptTrue)
+        updateBatteryLevel(powerStatus2.getBatteryChargePercent());
 #ifdef DEBUG_HEAP
     if (lastheap != memGet.getFreeHeap()) {
         // Use stack-allocated buffer to avoid heap allocations in monitoring code

src/PowerFSM.cpp

@@ -219,7 +219,11 @@ static void darkEnter()
 static void serialEnter()
 {
     LOG_POWERFSM("State: serialEnter");
+#ifndef ARCH_NRF52
+    // nRF52 runs BLE on SoftDevice independently of USB serial — no need to disable it.
+    // (Same rationale as nbEnter() which already guards this with #ifdef ARCH_ESP32)
     setBluetoothEnable(false);
+#endif
     if (screen) {
         screen->setOn(true);
     }

src/RedirectablePrint.cpp

@@ -7,6 +7,7 @@
 #include "memGet.h"
 #include "mesh/generated/meshtastic/mesh.pb.h"
 #include <assert.h>
+#include <atomic>
 #include <cstring>
 #include <memory>
 #include <stdexcept>
@@ -20,6 +21,22 @@
 #if HAS_NETWORKING
 extern meshtastic::Syslog syslog;
 #endif
+
+namespace
+{
+std::atomic<bool> serialHalLogSuppressed{false};
+}
+
+void RedirectablePrint::setSerialHalLogSuppressed(bool suppressed)
+{
+    serialHalLogSuppressed.store(suppressed);
+}
+
+bool RedirectablePrint::isSerialHalLogSuppressed()
+{
+    return serialHalLogSuppressed.load();
+}
+
 void RedirectablePrint::rpInit()
 {
 #ifdef HAS_FREE_RTOS
@@ -281,6 +298,10 @@ meshtastic_LogRecord_Level RedirectablePrint::getLogLevel(const char *logLevel)
 void RedirectablePrint::log(const char *logLevel, const char *format, ...)
 {
 
+    if (isSerialHalLogSuppressed()) {
+        return;
+    }
+
     // append \n to format
     size_t len = strlen(format);
     auto newFormat = std::unique_ptr<char[]>(new char[len + 2]);

src/RedirectablePrint.h

@@ -24,6 +24,11 @@ class RedirectablePrint : public Print
   public:
     explicit RedirectablePrint(Print *_dest) : dest(_dest) {}
 
+    /// Suppress all log output while a SerialHal transaction is in progress.
+    // Unclear if this is necessary, but it seems to help with response speeds.
+    static void setSerialHalLogSuppressed(bool suppressed);
+    static bool isSerialHalLogSuppressed();
+
     /**
      * Set a new destination
      */

src/configuration.h

@@ -179,6 +179,13 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #endif
 #endif
 
+#ifdef USE_KCT8103L_PA_ONLY
+#if defined(HELTEC_MESH_TOWER_V2)
+#define NUM_PA_POINTS 22
+#define TX_GAIN_LORA 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 10, 10, 10, 10, 10, 10, 10, 10, 10, 9, 8, 7
+#endif
+#endif
+
 #ifdef RAK13302
 #define NUM_PA_POINTS 22
 #define TX_GAIN_LORA 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 8
@@ -573,5 +580,94 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define USE_ETHERNET_DEFAULT 0
 #endif
 
+// -----------------------------------------------------------------------------
+// MESHTASTIC_LOCKDOWN — runtime, client-toggleable hardening (nRF52 only)
+//
+// Lockdown/protect support is opt-in at build time. Builds that need it pass
+// -DMESHTASTIC_ENABLE_LOCKDOWN=1. When enabled on nRF52 (CC310 hardware
+// crypto), whether it is ACTIVE is decided entirely at runtime by
+// EncryptedStorage::isLockdownActive()
+// (== a passphrase has been provisioned, i.e. /prefs/.dek exists). A device
+// that has never been provisioned — or that the operator disabled from the
+// client app — behaves exactly like stock firmware: plaintext storage, no
+// redaction, normal logging, normal display.
+//
+// The operator toggles lockdown from the client app:
+//   off -> on : provision a passphrase (AdminMessage.lockdown_auth). The
+//               firmware generates a DEK, encrypts the stored config, and
+//               authorizes the connection.
+//   on -> off : AdminMessage.lockdown_auth { disable=true } with the
+//               passphrase — decrypts storage back to plaintext and removes
+//               the DEK / token / monotonic-counter / backoff files, then
+//               reboots into normal mode. APPROTECT is the one thing that
+//               does NOT revert (see below).
+//
+// MESHTASTIC_LOCKDOWN here is an INTERNAL capability marker. It gates the UI
+// bits (lock screen, pairing-PIN handling). Flash-constrained nRF52 variants
+// that genuinely cannot afford the ~tens-of-KB of crypto + access-control code
+// may also opt out with -DMESHTASTIC_EXCLUDE_LOCKDOWN=1.
+//
+//   MESHTASTIC_PHONEAPI_ACCESS_CONTROL — per-connection auth + redaction,
+//                                        gated at runtime on isLockdownActive()
+//   MESHTASTIC_ENCRYPTED_STORAGE       — AES-128-CTR + HMAC-SHA256 at-rest
+//   MESHTASTIC_ENABLE_APPROTECT        — UICR APPROTECT capability. The actual
+//                                        one-way burn happens at runtime, only
+//                                        once provisioned, only on non-vulnerable
+//                                        silicon, and is STICKY: disabling
+//                                        lockdown does NOT (cannot) reverse it.
+//
+// DEBUG_MUTE is intentionally NOT coupled to lockdown — a capable-but-off
+// device must log normally. Define DEBUG_MUTE separately for a silent build.
+//
+// -DMESHTASTIC_LOCKDOWN_DEBUG=1 keeps the irreversible APPROTECT burn disabled
+// even when provisioned — for development so dev boards never lose SWD.
+// -----------------------------------------------------------------------------
+#if defined(ARCH_NRF52)
+#ifndef MESHTASTIC_ENABLE_LOCKDOWN
+#define MESHTASTIC_ENABLE_LOCKDOWN 0
+#endif
+
+#if !MESHTASTIC_ENABLE_LOCKDOWN
+#undef MESHTASTIC_LOCKDOWN
+#undef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+#undef MESHTASTIC_ENCRYPTED_STORAGE
+#undef MESHTASTIC_ENABLE_APPROTECT
+#ifndef MESHTASTIC_EXCLUDE_LOCKDOWN
+#define MESHTASTIC_EXCLUDE_LOCKDOWN 1
+#endif
+#endif
+
+#if MESHTASTIC_ENABLE_LOCKDOWN && !defined(MESHTASTIC_EXCLUDE_LOCKDOWN)
+#define MESHTASTIC_LOCKDOWN 1
+#define MESHTASTIC_PHONEAPI_ACCESS_CONTROL 1
+#define MESHTASTIC_ENCRYPTED_STORAGE 1
+#ifndef MESHTASTIC_LOCKDOWN_DEBUG
+#define MESHTASTIC_ENABLE_APPROTECT 1
+#endif
+#endif
+#endif
+
+#ifdef MESHTASTIC_LOCKDOWN
+
+// Per-boot uptime cap on unlocked sessions. 0 = unlimited (token-only
+// enforcement, the existing behavior). When non-zero, every passphrase
+// unlock (and every token-auto-unlock that inherits the value) arms a
+// timer; on expiry the device lockNow()s and reboots into locked state.
+// Bounds the total exposure window to bootsRemaining * this value if an
+// attacker has physical possession but not the passphrase.
+//
+// Override at build time. Suggested:
+//   carry device:        3600  (1h sessions, periodic re-auth from phone)
+//   tower / infra node:  0     (default — relies on token TTLs only)
+//
+// A future LockdownAuth.max_session_seconds proto field will let the
+// client set this per-token; until that lands the build-time value is
+// the only source.
+#ifndef MESHTASTIC_LOCKDOWN_SESSION_DEFAULT_SECONDS
+#define MESHTASTIC_LOCKDOWN_SESSION_DEFAULT_SECONDS 0
+#endif
+
+#endif // MESHTASTIC_LOCKDOWN
+
 #include "DebugConfiguration.h"
 #include "RF95Configuration.h"

src/detect/ScanI2C.cpp

@@ -37,15 +37,15 @@ ScanI2C::FoundDevice ScanI2C::firstKeyboard() const
 
 ScanI2C::FoundDevice ScanI2C::firstAccelerometer() const
 {
-    ScanI2C::DeviceType types[] = {MPU6050, LIS3DH, BMA423, LSM6DS3, BMX160, STK8BAXX,
-                                   ICM20948, QMA6100P, BMM150,  BMI270,  ICM42607P};
-    return firstOfOrNONE(11, types);
+    ScanI2C::DeviceType types[] = {MPU6050,  LIS3DH,   BMA423, LSM6DS3, BMX160,    STK8BAXX,
+                                   ICM20948, QMA6100P, BMM150, BMI270,  ICM42607P, ISM330DHCX};
+    return firstOfOrNONE(12, types);
 }
 
 ScanI2C::FoundDevice ScanI2C::firstMagnetometer() const
 {
-    ScanI2C::DeviceType types[] = {MMC5983MA};
-    return firstOfOrNONE(1, types);
+    ScanI2C::DeviceType types[] = {MMC5983MA, IIS2MDCTR};
+    return firstOfOrNONE(2, types);
 }
 
 ScanI2C::FoundDevice ScanI2C::firstAQI() const

src/detect/ScanI2C.h

@@ -99,6 +99,8 @@ class ScanI2C
         CW2015,
         SCD30,
         ADS1115,
+        IIS2MDCTR,
+        ISM330DHCX,
     } DeviceType;
 
     // typedef uint8_t DeviceAddress;

src/detect/ScanI2CTwoWire.cpp

@@ -8,7 +8,7 @@
 #if defined(ARCH_PORTDUINO)
 #include "linux/LinuxHardwareI2C.h"
 #endif
-#if !defined(ARCH_PORTDUINO) && !defined(ARCH_STM32WL)
+#if !defined(ARCH_PORTDUINO) && !defined(ARCH_STM32)
 #include "meshUtils.h" // vformat
 
 #endif
@@ -584,6 +584,9 @@ void ScanI2CTwoWire::scanPort(I2CPort port, uint8_t *address, uint8_t asize)
                 if (registerValue == 0x6A) {
                     type = LSM6DS3;
                     logFoundDevice("LSM6DS3", (uint8_t)addr.address);
+                } else if (registerValue == 0x6B) {
+                    type = ISM330DHCX;
+                    logFoundDevice("ISM330DHCX", (uint8_t)addr.address);
                 } else {
                     type = QMI8658;
                     logFoundDevice("QMI8658", (uint8_t)addr.address);
@@ -591,7 +594,17 @@ void ScanI2CTwoWire::scanPort(I2CPort port, uint8_t *address, uint8_t asize)
                 break;
 
                 SCAN_SIMPLE_CASE(QMC5883L_ADDR, QMC5883L, "QMC5883L", (uint8_t)addr.address)
-                SCAN_SIMPLE_CASE(HMC5883L_ADDR, HMC5883L, "HMC5883L", (uint8_t)addr.address)
+            case HMC5883L_ADDR:
+                registerValue = getRegisterValue(ScanI2CTwoWire::RegisterLocation(addr, 0x4FU), 1); // get ID
+                if (registerValue == 0x40) {
+                    type = IIS2MDCTR;
+                    logFoundDevice("IIS2MDCTR", (uint8_t)addr.address);
+                    break;
+                } else {
+                    type = HMC5883L;
+                    logFoundDevice("HMC5883L", (uint8_t)addr.address);
+                    break;
+                }
 #ifdef HAS_QMA6100P
                 SCAN_SIMPLE_CASE(QMA6100P_ADDR, QMA6100P, "QMA6100P", (uint8_t)addr.address)
 #else

src/gps/GPS.cpp

@@ -17,7 +17,10 @@
 #include "main.h" // pmu_found
 #include "sleep.h"
 
+#include "FSCommon.h"
 #include "GPSUpdateScheduling.h"
+#include "SPILock.h"
+#include "SafeFile.h"
 #include "cas.h"
 #include "ubx.h"
 
@@ -44,7 +47,7 @@ template <typename T, std::size_t N> std::size_t array_count(const T (&)[N])
 
 #if defined(ARCH_NRF52)
 Uart *GPS::_serial_gps = &GPS_SERIAL_PORT;
-#elif defined(ARCH_ESP32) || defined(ARCH_PORTDUINO) || defined(ARCH_STM32WL)
+#elif defined(ARCH_ESP32) || defined(ARCH_PORTDUINO) || defined(ARCH_STM32)
 HardwareSerial *GPS::_serial_gps = &GPS_SERIAL_PORT;
 #elif defined(ARCH_RP2040)
 SerialUART *GPS::_serial_gps = &GPS_SERIAL_PORT;
@@ -71,6 +74,112 @@ static struct uBloxGnssModelInfo {
 #define GPS_SOL_EXPIRY_MS 5000 // in millis. give 1 second time to combine different sentences. NMEA Frequency isn't higher anyway
 #define NMEA_MSG_GXGSA "GNGSA" // GSA message (GPGSA, GNGSA etc)
 
+namespace
+{
+// Versioned on-disk record for persisted GPS probe results.
+constexpr uint32_t GPS_PROBE_CACHE_MAGIC = 0x47504348UL; // "GPCH"
+constexpr uint16_t GPS_PROBE_CACHE_VERSION = 1;
+constexpr const char *GPS_PROBE_CACHE_FILE = "/prefs/gps_probe_cache.dat";
+constexpr int MIN_PLAUSIBLE_GPS_YEAR = 2020;
+constexpr int MAX_PLAUSIBLE_GPS_YEAR = 2100;
+#ifdef TRACKER_T1000_E
+constexpr uint32_t T1000_E_AIROHA_WAKE_MS = 1000;
+constexpr uint32_t T1000_E_AIROHA_WAKE_INTERVAL_MS = 40;
+#endif
+
+struct GPSProbeCacheRecord {
+    uint32_t magic;
+    uint16_t version;
+    uint16_t reserved;
+    uint32_t baud;
+    uint8_t model;
+};
+
+bool isValidGnssModel(uint8_t model)
+{
+    // Keep persisted values bounded to known enum range.
+    return model <= static_cast<uint8_t>(GNSS_MODEL_CM121);
+}
+
+bool isValidProbeBaud(uint32_t baud)
+{
+    // Conservative sanity range for UART baud values.
+    return baud >= 1200 && baud <= 921600;
+}
+
+template <typename T> void wakeAirohaForActiveProbe(T *serialGps)
+{
+#ifdef TRACKER_T1000_E
+    digitalWrite(PIN_GPS_EN, GPS_EN_ACTIVE);
+    digitalWrite(GPS_RTC_INT, HIGH);
+    delay(3);
+    digitalWrite(GPS_RTC_INT, LOW);
+    delay(50);
+
+    const uint32_t start = millis();
+    do {
+        serialGps->write("$PAIR382,1*2E\r\n");
+        delay(T1000_E_AIROHA_WAKE_INTERVAL_MS);
+    } while (Throttle::isWithinTimespanMs(start, T1000_E_AIROHA_WAKE_MS));
+#elif defined(GNSS_AIROHA)
+    serialGps->write("$PAIR382,1*2E\r\n");
+    delay(20);
+#else
+    (void)serialGps;
+#endif
+}
+
+bool isPlausibleNmeaTime(const struct tm &t)
+{
+    const int year = t.tm_year + 1900;
+    if (year < MIN_PLAUSIBLE_GPS_YEAR || year > MAX_PLAUSIBLE_GPS_YEAR) {
+        return false;
+    }
+
+#ifdef BUILD_EPOCH
+    const int64_t candidate = static_cast<int64_t>(gm_mktime(&t));
+    const int64_t minEpoch = static_cast<int64_t>(BUILD_EPOCH);
+    const int64_t maxEpoch = minEpoch + static_cast<int64_t>(FORTY_YEARS);
+    return candidate >= minEpoch && candidate <= maxEpoch;
+#else
+    return true;
+#endif
+}
+
+template <typename T> bool sawNmeaSentenceAtBaud(T *serialGps, uint32_t timeoutMs)
+{
+    // Lightweight passive check: look for at least one complete
+    // "$...,<field>\n" style NMEA sentence.
+    const uint32_t deadline = millis() + timeoutMs;
+    bool sawDollar = false;
+    bool sawComma = false;
+
+    while ((int32_t)(millis() - deadline) < 0) {
+        while (serialGps->available()) {
+            char c = static_cast<char>(serialGps->read());
+            if (c == '$') {
+                sawDollar = true;
+                sawComma = false;
+                continue;
+            }
+            if (c == ',') {
+                sawComma = true;
+            }
+            if (c == '\n' || c == '\r') {
+                if (sawDollar && sawComma) {
+                    return true;
+                }
+                sawDollar = false;
+                sawComma = false;
+            }
+        }
+        delay(10);
+    }
+
+    return false;
+}
+} // namespace
+
 // For logging
 static const char *getGPSPowerStateString(GPSPowerState state)
 {
@@ -492,6 +601,201 @@ static const int rareSerialSpeeds[3] = {4800, 57600, GPS_BAUDRATE};
 #define GPS_PROBETRIES 2
 #endif
 
+bool GPS::loadProbeCache()
+{
+#ifdef FSCom
+    // Load the last known-good GPS model/baud pair so we can avoid a full probe
+    // sweep on every boot.
+    triedProbeCache = true; // Latch this boot's load attempt, even if no cache.
+    GPSProbeCacheRecord record = {};
+    size_t bytesRead = 0;
+
+    spiLock->lock();
+    auto file = FSCom.open(GPS_PROBE_CACHE_FILE, FILE_O_READ);
+    if (!file) {
+        spiLock->unlock();
+        return false;
+    }
+    bytesRead = file.read(reinterpret_cast<uint8_t *>(&record), sizeof(record));
+    file.close();
+    spiLock->unlock();
+
+    const bool headerValid = (bytesRead == sizeof(record)) && (record.magic == GPS_PROBE_CACHE_MAGIC) &&
+                             (record.version == GPS_PROBE_CACHE_VERSION) && (record.reserved == 0U);
+    if (!headerValid || !isValidGnssModel(record.model) || !isValidProbeBaud(record.baud)) {
+        clearProbeCache(); // Drop corrupt/invalid cache so next boot can
+                           // recover.
+        return false;
+    }
+
+    cachedProbeBaud = static_cast<int32_t>(record.baud);
+    cachedProbeModel = static_cast<GnssModel_t>(record.model);
+    hasProbeCache = true;
+    triedProbeCache = false;
+    LOG_INFO("Loaded cached GPS probe: baud=%u", record.baud);
+    return true;
+#else
+    return false;
+#endif
+}
+
+void GPS::clearProbeCache()
+{
+    // Invalidate in-memory and on-disk cache so next boot is forced to do a
+    // full probe.
+    hasProbeCache = false;
+    triedProbeCache = true;
+    cachedProbeBaud = 0;
+    cachedProbeModel = GNSS_MODEL_UNKNOWN;
+#ifdef FSCom
+    spiLock->lock();
+    if (FSCom.exists(GPS_PROBE_CACHE_FILE)) {
+        FSCom.remove(GPS_PROBE_CACHE_FILE);
+    }
+    spiLock->unlock();
+#endif
+}
+
+bool GPS::saveProbeCache() const
+{
+#ifdef FSCom
+    if (gnssModel == GNSS_MODEL_UNKNOWN || !isValidGnssModel(static_cast<uint8_t>(gnssModel)) ||
+        !isValidProbeBaud(detectedBaud)) {
+        return false;
+    }
+
+    spiLock->lock();
+    FSCom.mkdir("/prefs");
+    spiLock->unlock();
+    GPSProbeCacheRecord record = {
+        GPS_PROBE_CACHE_MAGIC, GPS_PROBE_CACHE_VERSION, 0, static_cast<uint32_t>(detectedBaud), static_cast<uint8_t>(gnssModel),
+    };
+
+    auto file = SafeFile(GPS_PROBE_CACHE_FILE, true);
+    spiLock->lock();
+    const size_t written = file.write(reinterpret_cast<const uint8_t *>(&record), sizeof(record));
+    spiLock->unlock();
+    return (written == sizeof(record)) && file.close();
+#else
+    return false;
+#endif
+}
+
+bool GPS::verifyCachedProbePresence()
+{
+    if (!hasProbeCache || cachedProbeModel == GNSS_MODEL_UNKNOWN || !isValidProbeBaud(cachedProbeBaud)) {
+        return false;
+    }
+
+#if defined(ARCH_NRF52) || defined(ARCH_PORTDUINO) || defined(ARCH_STM32)
+    _serial_gps->end();
+    _serial_gps->begin(cachedProbeBaud);
+#elif defined(ARCH_RP2040)
+    _serial_gps->end();
+    _serial_gps->setFIFOSize(256);
+    _serial_gps->begin(cachedProbeBaud);
+#else
+    if (_serial_gps->baudRate() != cachedProbeBaud) {
+        LOG_DEBUG("Set GPS Baud to %i (cached verify)", cachedProbeBaud);
+        _serial_gps->updateBaudRate(cachedProbeBaud);
+    }
+#endif
+
+    // Before trusting cached model/baud, require either active model-specific
+    // response or passive NMEA flow.
+    clearBuffer();
+    bool present = false;
+
+    // Model-specific "active ping" checks to avoid false stale decisions on
+    // modules that start streaming late.
+    const char *cachedProbeModelName = "UNKNOWN";
+    switch (cachedProbeModel) {
+    case GNSS_MODEL_MTK:
+        cachedProbeModelName = "L76K/MTK";
+        _serial_gps->write("$PCAS06,0*1B\r\n");
+        present = (getACK("$GPTXT,01,01,02,SW=", 700) == GNSS_RESPONSE_OK);
+        break;
+    case GNSS_MODEL_MTK_L76B:
+        cachedProbeModelName = "L76B";
+    case GNSS_MODEL_MTK_PA1010D:
+        if (cachedProbeModel == GNSS_MODEL_MTK_PA1010D)
+            cachedProbeModelName = "PA1010D";
+    case GNSS_MODEL_MTK_PA1616S:
+        if (cachedProbeModel == GNSS_MODEL_MTK_PA1616S)
+            cachedProbeModelName = "PA1616S";
+    case GNSS_MODEL_LS20031:
+        if (cachedProbeModel == GNSS_MODEL_LS20031)
+            cachedProbeModelName = "LS20031";
+        _serial_gps->write("$PMTK605*31\r\n");
+        present = (getACK("$PMTK705", 900) == GNSS_RESPONSE_OK);
+        break;
+    case GNSS_MODEL_AG3335:
+        cachedProbeModelName = "AG3335";
+    case GNSS_MODEL_AG3352:
+        if (cachedProbeModel == GNSS_MODEL_AG3352)
+            cachedProbeModelName = "AG3352";
+        wakeAirohaForActiveProbe(_serial_gps);
+        _serial_gps->write("$PAIR021*39\r\n");
+        present = (getACK("$PAIR021,", 900) == GNSS_RESPONSE_OK);
+        break;
+    case GNSS_MODEL_ATGM336H:
+        cachedProbeModelName = "ATGM336H";
+        _serial_gps->write("$PCAS06,1*1A\r\n");
+        present = (getACK("$GPTXT,01,01,02,HW=ATGM", 900) == GNSS_RESPONSE_OK);
+        break;
+    case GNSS_MODEL_UC6580:
+        cachedProbeModelName = "UC6580/UM600";
+        _serial_gps->write("$PDTINFO\r\n");
+        present = (getACK("UC6580", 900) == GNSS_RESPONSE_OK) || (getACK("UM600", 900) == GNSS_RESPONSE_OK);
+        break;
+    case GNSS_MODEL_CM121:
+        cachedProbeModelName = "CM121";
+        _serial_gps->write("$PDTINFO\r\n");
+        present = (getACK("CM121", 900) == GNSS_RESPONSE_OK);
+        break;
+    case GNSS_MODEL_UBLOX6:
+    case GNSS_MODEL_UBLOX7:
+    case GNSS_MODEL_UBLOX8:
+    case GNSS_MODEL_UBLOX9:
+    case GNSS_MODEL_UBLOX10: {
+        if (cachedProbeModel == GNSS_MODEL_UBLOX6)
+            cachedProbeModelName = "U-blox 6";
+        else if (cachedProbeModel == GNSS_MODEL_UBLOX7)
+            cachedProbeModelName = "U-blox 7";
+        else if (cachedProbeModel == GNSS_MODEL_UBLOX8)
+            cachedProbeModelName = "U-blox 8";
+        else if (cachedProbeModel == GNSS_MODEL_UBLOX9)
+            cachedProbeModelName = "U-blox 9";
+        else if (cachedProbeModel == GNSS_MODEL_UBLOX10)
+            cachedProbeModelName = "U-blox 10";
+
+        uint8_t cfg_rate[] = {0xB5, 0x62, 0x06, 0x08, 0x00, 0x00, 0x00, 0x00};
+        UBXChecksum(cfg_rate, sizeof(cfg_rate));
+        _serial_gps->write(cfg_rate, sizeof(cfg_rate));
+        present = (getACK(0x06, 0x08, 900) != GNSS_RESPONSE_NONE);
+        break;
+    }
+    default:
+        break;
+    }
+
+    if (!present) {
+        // Some modules may not respond to probes while still streaming NMEA, so
+        // allow a passive fallback check.
+        present = sawNmeaSentenceAtBaud(_serial_gps, 3000);
+    }
+    if (!present) {
+        LOG_WARN("Cached GPS probe is stale (%s @ %d), clearing cache", cachedProbeModelName, cachedProbeBaud);
+        clearProbeCache();
+        return false;
+    }
+
+    detectedBaud = cachedProbeBaud;
+    gnssModel = cachedProbeModel;
+    LOG_INFO("Using cached GPS probe: %s @ %d", cachedProbeModelName, detectedBaud);
+    return true;
+}
+
 /**
  * @brief  Setup the GPS based on the model detected.
  *  We detect the GPS by cycling through a set of baud rates, first common then rare.
@@ -504,24 +808,39 @@ bool GPS::setup()
     if (!didSerialInit) {
         int msglen = 0;
         if (tx_gpio && gnssModel == GNSS_MODEL_UNKNOWN) {
-            if (probeTries < GPS_PROBETRIES) {
+            if (!hasProbeCache && !triedProbeCache) {
+                (void)loadProbeCache();
+            }
+
+            if (hasProbeCache && !triedProbeCache) {
+                triedProbeCache = true;
+                if (!verifyCachedProbePresence()) {
+                    currentStep = 0;
+                    speedSelect = 0;
+                    probeTries = 0;
+                }
+            }
+
+            if (gnssModel == GNSS_MODEL_UNKNOWN && probeTries < GPS_PROBETRIES) {
+                // No usable cache: walk common baud rates first.
                 gnssModel = probe(serialSpeeds[speedSelect]);
-                if (gnssModel == GNSS_MODEL_UNKNOWN) {
-                    if (currentStep == 0 && ++speedSelect == array_count(serialSpeeds)) {
-                        speedSelect = 0;
-                        ++probeTries;
-                    }
+                if (gnssModel != GNSS_MODEL_UNKNOWN) {
+                    detectedBaud = serialSpeeds[speedSelect];
+                } else if (currentStep == 0 && ++speedSelect == array_count(serialSpeeds)) {
+                    speedSelect = 0;
+                    ++probeTries;
                 }
             }
             // Rare Serial Speeds
 #ifndef CONFIG_IDF_TARGET_ESP32C6
-            if (probeTries == GPS_PROBETRIES) {
+            else if (gnssModel == GNSS_MODEL_UNKNOWN && probeTries == GPS_PROBETRIES) {
+                // Then try less common baud rates before giving up.
                 gnssModel = probe(rareSerialSpeeds[speedSelect]);
-                if (gnssModel == GNSS_MODEL_UNKNOWN) {
-                    if (currentStep == 0 && ++speedSelect == array_count(rareSerialSpeeds)) {
-                        LOG_WARN("Give up on GPS probe and set to %d", GPS_BAUDRATE);
-                        return true;
-                    }
+                if (gnssModel != GNSS_MODEL_UNKNOWN) {
+                    detectedBaud = rareSerialSpeeds[speedSelect];
+                } else if (currentStep == 0 && ++speedSelect == array_count(rareSerialSpeeds)) {
+                    LOG_WARN("Give up on GPS probe and set to %d", GPS_BAUDRATE);
+                    return true;
                 }
             }
 #endif
@@ -529,6 +848,7 @@ bool GPS::setup()
 
         if (gnssModel != GNSS_MODEL_UNKNOWN) {
             setConnected();
+            (void)saveProbeCache();
         } else {
             return false;
         }
@@ -840,10 +1160,22 @@ void GPS::setPowerState(GPSPowerState newState, uint32_t sleepTime)
     switch (newState) {
     case GPS_ACTIVE:
     case GPS_IDLE:
-        if (oldState == GPS_ACTIVE || oldState == GPS_IDLE) // If hardware already awake, no changes needed
+        if (oldState == GPS_ACTIVE)
+            break;
+        gotTime = false;
+        if (oldState == GPS_IDLE) // If hardware already awake, no changes needed
             break;
         if (oldState != GPS_ACTIVE && oldState != GPS_IDLE) // If hardware just waking now, clear buffer
             clearBuffer();
+#ifdef TRACKER_T1000_E
+        pinMode(GPS_VRTC_EN, OUTPUT);
+        digitalWrite(GPS_VRTC_EN, HIGH);
+        pinMode(GPS_SLEEP_INT, OUTPUT);
+        digitalWrite(GPS_SLEEP_INT, HIGH);
+        pinMode(GPS_RTC_INT, OUTPUT);
+        digitalWrite(GPS_RTC_INT, LOW);
+        pinMode(GPS_RESETB_OUT, INPUT_PULLUP);
+#endif
         powerMon->setState(meshtastic_PowerMon_State_GPS_Active); // Report change for power monitoring (during testing)
         writePinEN(true);                                         // Power (EN pin): on
         setPowerPMU(true);                                        // Power (PMU): on
@@ -1102,6 +1434,11 @@ int32_t GPS::runOnce()
         if (!setup())
             return currentDelay; // Setup failed, re-run in two seconds
 
+        if (gnssModel == GNSS_MODEL_UNKNOWN) {
+            LOG_WARN("GPS not detected; marked not present for this boot");
+            return disable();
+        }
+
         // We have now loaded our saved preferences from flash
         if (config.position.gps_mode != meshtastic_Config_PositionConfig_GpsMode_ENABLED) {
             return disable();
@@ -1150,8 +1487,7 @@ int32_t GPS::runOnce()
         // if gps_update_interval is <=10s, GPS never goes off, so we treat that differently
         uint32_t updateInterval = Default::getConfiguredOrDefaultMs(config.position.gps_update_interval);
 
-        // 1. Got a time for the first time
-        bool gotTime = (getRTCQuality() >= RTCQualityGPS);
+        // 1. Got a time for the first time this cycle
         if (!gotTime && lookForTime()) { // Note: we count on this && short-circuiting and not resetting the RTC time
             gotTime = true;
         }
@@ -1277,7 +1613,7 @@ GnssModel_t GPS::probe(int serialSpeed)
 
     switch (currentStep) {
     case 0: {
-#if defined(ARCH_NRF52) || defined(ARCH_PORTDUINO) || defined(ARCH_STM32WL)
+#if defined(ARCH_NRF52) || defined(ARCH_PORTDUINO) || defined(ARCH_STM32)
         _serial_gps->end();
         _serial_gps->begin(serialSpeed);
 #elif defined(ARCH_RP2040)
@@ -1298,6 +1634,9 @@ GnssModel_t GPS::probe(int serialSpeed)
         digitalWrite(PIN_GPS_RESET, GPS_RESET_MODE); // assert for 10ms
         delay(10);
         digitalWrite(PIN_GPS_RESET, !GPS_RESET_MODE);
+#ifdef TRACKER_T1000_E
+        delay(100);
+#endif
 
         // attempt to detect the chip based on boot messages
         std::vector<ChipInfo> passive_detect = {
@@ -1350,6 +1689,7 @@ GnssModel_t GPS::probe(int serialSpeed)
     }
     case 3: {
         /* Airoha (Mediatek) AG3335A/M/S, A3352Q, Quectel L89 2.0, SimCom SIM65M */
+        wakeAirohaForActiveProbe(_serial_gps);
         _serial_gps->write("$PAIR062,2,0*3C\r\n"); // GSA OFF to reduce volume
         _serial_gps->write("$PAIR062,3,0*3D\r\n"); // GSV OFF to reduce volume
         _serial_gps->write("$PAIR513*3D\r\n");     // save configuration
@@ -1634,7 +1974,7 @@ std::unique_ptr<GPS> GPS::createGps()
 #elif defined(ARCH_NRF52)
         _serial_gps->setPins(new_gps->rx_gpio, new_gps->tx_gpio);
         _serial_gps->begin(GPS_BAUDRATE);
-#elif defined(ARCH_STM32WL)
+#elif defined(ARCH_STM32)
         _serial_gps->setTx(new_gps->tx_gpio);
         _serial_gps->setRx(new_gps->rx_gpio);
         _serial_gps->begin(GPS_BAUDRATE);
@@ -1681,6 +2021,9 @@ The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of s
         t.tm_year = d.year() - 1900;
         t.tm_isdst = false;
         if (t.tm_mon > -1) {
+            if (!isPlausibleNmeaTime(t)) {
+                return false;
+            }
             if (perhapsSetRTC(RTCQualityGPS, t) == RTCSetResultSuccess) {
                 LOG_DEBUG("NMEA GPS time set %02d-%02d-%02d %02d:%02d:%02d age %d", d.year(), d.month(), t.tm_mday, t.tm_hour,
                           t.tm_min, t.tm_sec, ti.age());

src/gps/GPS.h

@@ -155,14 +155,26 @@ class GPS : private concurrency::OSThread
      * @return true if we've acquired a new location
      */
     virtual bool lookForLocation();
+    // Load persisted GPS model+baud from /prefs.
+    bool loadProbeCache();
+    // Clear persisted GPS model+baud cache.
+    void clearProbeCache();
+    // Persist the currently detected GPS model+baud.
+    bool saveProbeCache() const;
+    // Verify the cached model+baud still maps to a live GPS device.
+    bool verifyCachedProbePresence();
 
     GnssModel_t gnssModel = GNSS_MODEL_UNKNOWN;
+    int32_t detectedBaud = GPS_BAUDRATE;
+    int32_t cachedProbeBaud = 0;
+    GnssModel_t cachedProbeModel = GNSS_MODEL_UNKNOWN;
 
     TinyGPSPlus reader;
     uint8_t fixQual = 0; // fix quality from GPGGA
     uint32_t lastChecksumFailCount = 0;
     uint8_t currentStep = 0;
     int32_t currentDelay = 2000;
+    bool gotTime = false;
 
 #ifndef TINYGPS_OPTION_NO_CUSTOM_FIELDS
     // (20210908) TinyGps++ can only read the GPGSA "FIX TYPE" field
@@ -178,6 +190,10 @@ class GPS : private concurrency::OSThread
 
     uint8_t speedSelect = 0;
     uint8_t probeTries = 0;
+    // Cache file is successfully loaded.
+    bool hasProbeCache = false;
+    // Ensures cached probe is attempted once per boot.
+    bool triedProbeCache = false;
 
     /**
      * hasValidLocation - indicates that the position variables contain a complete

src/gps/RTC.cpp

@@ -219,8 +219,8 @@ RTCSetResult perhapsSetRTC(RTCQuality q, const struct timeval *tv, bool forceUpd
     } else if (q == RTCQualityGPS) {
         shouldSet = true;
         LOG_DEBUG("Reapply GPS time: %ld secs", printableEpoch);
-    } else if (q == RTCQualityNTP && !Throttle::isWithinTimespanMs(lastSetMsec, (12 * 60 * 60 * 1000UL))) {
-        // Every 12 hrs we will slam in a new NTP or Phone GPS / NTP time, to correct for local RTC clock drift
+    } else if (q == RTCQualityNTP && !Throttle::isWithinTimespanMs(lastSetMsec, (30 * 60 * 1000UL))) {
+        // Every 30 minutes we will slam in a new NTP or Phone GPS / NTP time, to correct for local RTC clock drift
         shouldSet = true;
         LOG_DEBUG("Reapply external time to correct clock drift %ld secs", printableEpoch);
     } else {

src/graphics/Screen.cpp

@@ -41,6 +41,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "draw/UIRenderer.h"
 #include "graphics/TFTColorRegions.h"
 #include "modules/CannedMessageModule.h"
+#include "security/LockdownDisplay.h"
 
 #if !MESHTASTIC_EXCLUDE_GPS
 #include "GPS.h"
@@ -50,6 +51,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "MeshService.h"
 #include "MessageStore.h"
 #include "RadioLibInterface.h"
+#include "SPILock.h"
 #include "error.h"
 #include "gps/GeoCoord.h"
 #include "gps/RTC.h"
@@ -118,8 +120,76 @@ static inline void prepareFrameColorRegions()
 }
 #endif
 
+#ifdef MESHTASTIC_LOCKDOWN
+// Static lock screen drawn in place of normal frames when
+// meshtastic_security::shouldRedactDisplay() returns true. Renders centered
+// "LOCKED" plus battery so the operator can see the device is alive and
+// charged without leaking any node/channel/message/position content.
+// Draw the LOCKED frame into the host-side framebuffer. Does NOT commit
+// to the panel — the caller is responsible for calling display->display()
+// once it has composited any overlays on top. Committing here would cause
+// visible flicker between "just LOCKED" and "LOCKED + banner overlay" when
+// the pairing-PIN special-case in updateUiFrame paints the overlay after
+// this returns.
+static void drawLockdownLockScreenIntoBuffer(OLEDDisplay *display)
+{
+    display->clear();
+
+    const int w = display->getWidth();
+    const int h = display->getHeight();
+
+    display->setTextAlignment(TEXT_ALIGN_CENTER);
+    display->setFont(FONT_LARGE);
+    display->drawString(w / 2, h / 2 - FONT_HEIGHT_LARGE, "LOCKED");
+
+    display->setFont(FONT_SMALL);
+    char status[32] = "Connect to unlock";
+    if (powerStatus && powerStatus->getHasBattery()) {
+        int pct = powerStatus->getBatteryChargePercent();
+        snprintf(status, sizeof(status), "Battery %d%%", pct);
+    }
+    display->drawString(w / 2, h / 2 + 2, status);
+}
+
+// Convenience wrapper for callers that want the LOCKED frame committed
+// to the panel immediately and have no overlay to compose on top.
+static void drawLockdownLockScreen(OLEDDisplay *display)
+{
+    drawLockdownLockScreenIntoBuffer(display);
+    display->display();
+}
+#endif
+
 static inline void updateUiFrame(OLEDDisplayUi *ui)
 {
+#ifdef MESHTASTIC_LOCKDOWN
+    if (meshtastic_security::shouldRedactDisplay() && screen != nullptr) {
+        OLEDDisplay *display = screen->getDisplayDevice();
+        // Paint LOCKED into the framebuffer WITHOUT committing. We commit
+        // exactly once at the bottom — after any overlay has been composed
+        // on top — so the panel never visibly transitions from "just LOCKED"
+        // to "LOCKED + overlay" mid-frame. Committing twice per cycle was
+        // the source of the H13 flicker.
+        drawLockdownLockScreenIntoBuffer(display);
+        // Special-case the BLE pairing PIN banner. The PIN is needed to
+        // complete first-pair against a locked device, but the lockdown
+        // short-circuit would otherwise hide the PIN entirely. The PIN is
+        // a per-attempt ephemeral pair-handshake artifact, not operator
+        // content, so compositing it over the LOCKED frame is safe.
+        //
+        // Calling ui->update() here would be wrong: it redraws the current
+        // carousel frame (the dashboard) into the framebuffer before the
+        // overlay paints, leaving operator content visible underneath the
+        // banner. Instead we invoke the banner overlay callback directly,
+        // which paints only the banner box on top of the LOCKED pixels we
+        // already have in the framebuffer.
+        if (NotificationRenderer::current_notification_type == notificationTypeEnum::pairing_pin) {
+            NotificationRenderer::drawBannercallback(display, ui->getUiState());
+        }
+        display->display();
+        return;
+    }
+#endif
 #if GRAPHICS_TFT_COLORING_ENABLED
     prepareFrameColorRegions();
 #endif
@@ -163,6 +233,16 @@ static inline float wrapHeading360(float heading)
     return heading;
 }
 
+static inline float wrapDelta180(float delta)
+{
+    if (delta > 180.0f) {
+        delta -= 360.0f;
+    } else if (delta < -180.0f) {
+        delta += 360.0f;
+    }
+    return delta;
+}
+
 void Screen::setHeading(float heading)
 {
     const float wrappedHeading = wrapHeading360(heading);
@@ -174,37 +254,30 @@ void Screen::setHeading(float heading)
     }
 
     // Interpolate using shortest-path angular delta to avoid jumps around 0/360.
-    float delta = wrappedHeading - compassHeading;
-    if (delta > 180.0f) {
-        delta -= 360.0f;
-    } else if (delta < -180.0f) {
-        delta += 360.0f;
-    }
+    float delta = wrapDelta180(wrappedHeading - compassHeading);
 
     // Adaptive filtering:
     // - Strong damping for tiny deltas (jitter)
     // - Faster response for larger turns
     const float absDelta = (delta >= 0.0f) ? delta : -delta;
-    if (absDelta < 1.0f) {
-        return;
-    }
+    if (absDelta >= 1.0f) {
+        float alpha = 0.35f;
+        if (absDelta > 25.0f) {
+            alpha = 0.85f;
+        } else if (absDelta > 10.0f) {
+            alpha = 0.65f;
+        }
 
-    float alpha = 0.35f;
-    if (absDelta > 25.0f) {
-        alpha = 0.85f;
-    } else if (absDelta > 10.0f) {
-        alpha = 0.65f;
-    }
+        float step = delta * alpha;
+        const float maxStep = 12.0f;
+        if (step > maxStep) {
+            step = maxStep;
+        } else if (step < -maxStep) {
+            step = -maxStep;
+        }
 
-    float step = delta * alpha;
-    const float maxStep = 12.0f;
-    if (step > maxStep) {
-        step = maxStep;
-    } else if (step < -maxStep) {
-        step = -maxStep;
+        compassHeading = wrapHeading360(compassHeading + step);
     }
-
-    compassHeading = wrapHeading360(compassHeading + step);
 }
 
 // ==============================
@@ -582,6 +655,21 @@ void Screen::handleSetOn(bool on, FrameCallback einkScreensaver)
             setScreensaverFrames(einkScreensaver);
 #endif
 
+#ifdef MESHTASTIC_LOCKDOWN
+            // M19: before turning the panel off, paint a safe frame into the
+            // OLED's GDDRAM. The panel retains whatever was last written even
+            // while powered down, so when displayOn() is called later the
+            // screen would otherwise flash the previous frame's content for
+            // 16-50 ms before the next ui->update() lands. Painting the
+            // LOCKED frame now ensures the only thing the operator (or
+            // someone over their shoulder) can see on wake is the redacted
+            // view. Gated on lockdown — non-lockdown builds keep the
+            // previous frame as a UX cue that the display is just dimmed.
+            // dispdev is dereferenced unguarded throughout this file (incl.
+            // displayOff() just below), so no null check here.
+            drawLockdownLockScreen(dispdev);
+#endif
+
 #ifdef PIN_EINK_EN
             digitalWrite(PIN_EINK_EN, LOW);
 #elif defined(PCA_PIN_EINK_EN)
@@ -655,6 +743,10 @@ void Screen::setup()
         brightness = uiconfig.screen_brightness;
     }
 
+    // Restore which frames the user has hidden (persisted across reboots).
+    // Must happen before the first setFrames().
+    loadFrameVisibility();
+
     // Detect OLED subtype (if supported by board variant)
 #ifdef AutoOLEDWire_h
     if (isAUTOOled)
@@ -697,6 +789,27 @@ void Screen::setup()
 #endif
     LOG_INFO("Applied screen brightness: %d", brightness);
 
+#if defined(MESHTASTIC_LOCKDOWN) && defined(USE_EINK)
+    // M20: e-ink panels physically retain the last-rendered image without
+    // power, so a power-cycled lockdown handheld would keep showing
+    // operator-identifying content (position, messages, node info) until
+    // the firmware's first natural refresh — which on e-ink can be seconds
+    // into boot. Force a full refresh to the LOCKED frame here, immediately
+    // after the display is initialised and before any other rendering, so
+    // the persistent pixels are wiped to the redacted view before an
+    // observer can see them.
+    if (meshtastic_security::shouldRedactDisplay()) {
+        drawLockdownLockScreen(dispdev);
+#if defined(USE_EINK_PARALLELDISPLAY)
+        // Parallel-display variants drive refresh through a different path;
+        // a bare drawLockdownLockScreen above lands the frame into the
+        // panel buffer and the next ui->update() commits it as normal.
+#else
+        static_cast<EInkDisplay *>(dispdev)->forceDisplay();
+#endif
+    }
+#endif
+
     // Set custom overlay callbacks
     static OverlayCallback overlays[] = {
         graphics::UIRenderer::drawNavigationBar // Custom indicator icons for each frame
@@ -804,10 +917,16 @@ void Screen::setOn(bool on, FrameCallback einkScreensaver)
     if (cardKbI2cImpl)
         cardKbI2cImpl->toggleBacklight(on);
 #endif
-    if (!on)
+    if (!on) {
+#ifdef MESHTASTIC_LOCKDOWN
+        // Screen powering off (idle timeout, shutdown, deep sleep) latches
+        // the screen-lock. Next time the display wakes it shows the LOCKED
+        // frame until a client authenticates with the passphrase.
+        meshtastic_security::lockScreen();
+#endif
         // We handle off commands immediately, because they might be called because the CPU is shutting down
         handleSetOn(false, einkScreensaver);
-    else
+    } else
         enqueueCmd(ScreenCmd{.cmd = Cmd::SET_ON});
 }
 
@@ -914,7 +1033,17 @@ int32_t Screen::runOnce()
 #endif
 
 #ifndef DISABLE_WELCOME_UNSET
-    if (!NotificationRenderer::isOverlayBannerShowing() && config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_UNSET) {
+    bool suppressRegionOnboard = false;
+#ifdef MESHTASTIC_LOCKDOWN
+    // While lockdown is active and storage is still locked, config.lora.region
+    // is a deliberate UNSET placeholder — the real region lives in encrypted
+    // storage and is restored on unlock (see NodeDB's locked-boot path). Don't
+    // pop the region picker over the lock screen: it would trap input, and the
+    // operator can't set a region until they unlock anyway.
+    suppressRegionOnboard = meshtastic_security::shouldRedactDisplay();
+#endif
+    if (!suppressRegionOnboard && !NotificationRenderer::isOverlayBannerShowing() &&
+        config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_UNSET) {
 #if defined(OLED_TINY)
         menuHandler::LoraRegionPicker();
 #else
@@ -1416,6 +1545,9 @@ void Screen::toggleFrameVisibility(const std::string &frameName)
     if (frameName == "chirpy") {
         hiddenFrames.chirpy = !hiddenFrames.chirpy;
     }
+
+    // Save the new visibility state so it survives a reboot.
+    saveFrameVisibility();
 }
 
 bool Screen::isFrameHidden(const std::string &frameName) const
@@ -1454,6 +1586,167 @@ bool Screen::isFrameHidden(const std::string &frameName) const
     return false;
 }
 
+// ---------------------------------------------------------------------------
+// Frame visibility persistence
+//
+// The set of hideable frames varies by build (USE_EINK, HAS_GPS, ...), so we
+// serialize to a fixed bitmask where each frame name owns a permanent bit
+// position. Bits for frames that don't exist in the current build are simply
+// left untouched, which keeps the saved file portable across firmware variants.
+// ---------------------------------------------------------------------------
+namespace
+{
+static const char *frameVisibilityFileName = "/prefs/framevis";
+constexpr uint32_t FRAMEVIS_MAGIC = 0x53495646; // "FVIS" little-endian
+constexpr uint8_t FRAMEVIS_VERSION = 1;
+
+// Permanent bit assignments. Never renumber these; only append new ones.
+enum FrameVisBit : uint8_t {
+    FVBIT_TEXT_MESSAGE = 0,
+    FVBIT_WAYPOINT = 1,
+    FVBIT_WIFI = 2,
+    FVBIT_SYSTEM = 3,
+    FVBIT_HOME = 4,
+    FVBIT_CLOCK = 5,
+    FVBIT_NODELIST_NODES = 6,
+    FVBIT_NODELIST_LOCATION = 7,
+    FVBIT_NODELIST_LASTHEARD = 8,
+    FVBIT_NODELIST_HOPSIGNAL = 9,
+    FVBIT_NODELIST_DISTANCE = 10,
+    FVBIT_NODELIST_BEARINGS = 11,
+    FVBIT_GPS = 12,
+    FVBIT_LORA = 13,
+    FVBIT_SHOW_FAVORITES = 14,
+    FVBIT_CHIRPY = 15,
+};
+
+struct __attribute__((packed)) FrameVisFile {
+    uint32_t magic;
+    uint8_t version;
+    uint32_t mask;
+};
+
+inline void setBit(uint32_t &mask, uint8_t bit, bool value)
+{
+    if (value)
+        mask |= (1UL << bit);
+    else
+        mask &= ~(1UL << bit);
+}
+
+inline bool getBit(uint32_t mask, uint8_t bit)
+{
+    return (mask & (1UL << bit)) != 0;
+}
+} // namespace
+
+uint32_t Screen::packHiddenFrames() const
+{
+    uint32_t mask = 0;
+    setBit(mask, FVBIT_TEXT_MESSAGE, hiddenFrames.textMessage);
+    setBit(mask, FVBIT_WAYPOINT, hiddenFrames.waypoint);
+    setBit(mask, FVBIT_WIFI, hiddenFrames.wifi);
+    setBit(mask, FVBIT_SYSTEM, hiddenFrames.system);
+    setBit(mask, FVBIT_HOME, hiddenFrames.home);
+    setBit(mask, FVBIT_CLOCK, hiddenFrames.clock);
+#ifndef USE_EINK
+    setBit(mask, FVBIT_NODELIST_NODES, hiddenFrames.nodelist_nodes);
+    setBit(mask, FVBIT_NODELIST_LOCATION, hiddenFrames.nodelist_location);
+#endif
+#ifdef USE_EINK
+    setBit(mask, FVBIT_NODELIST_LASTHEARD, hiddenFrames.nodelist_lastheard);
+    setBit(mask, FVBIT_NODELIST_HOPSIGNAL, hiddenFrames.nodelist_hopsignal);
+    setBit(mask, FVBIT_NODELIST_DISTANCE, hiddenFrames.nodelist_distance);
+#endif
+#if HAS_GPS
+#ifdef USE_EINK
+    setBit(mask, FVBIT_NODELIST_BEARINGS, hiddenFrames.nodelist_bearings);
+#endif
+    setBit(mask, FVBIT_GPS, hiddenFrames.gps);
+#endif
+    setBit(mask, FVBIT_LORA, hiddenFrames.lora);
+    setBit(mask, FVBIT_SHOW_FAVORITES, hiddenFrames.show_favorites);
+    setBit(mask, FVBIT_CHIRPY, hiddenFrames.chirpy);
+    return mask;
+}
+
+void Screen::applyHiddenFramesMask(uint32_t mask)
+{
+    hiddenFrames.textMessage = getBit(mask, FVBIT_TEXT_MESSAGE);
+    hiddenFrames.waypoint = getBit(mask, FVBIT_WAYPOINT);
+    hiddenFrames.wifi = getBit(mask, FVBIT_WIFI);
+    hiddenFrames.system = getBit(mask, FVBIT_SYSTEM);
+    hiddenFrames.home = getBit(mask, FVBIT_HOME);
+    hiddenFrames.clock = getBit(mask, FVBIT_CLOCK);
+#ifndef USE_EINK
+    hiddenFrames.nodelist_nodes = getBit(mask, FVBIT_NODELIST_NODES);
+    hiddenFrames.nodelist_location = getBit(mask, FVBIT_NODELIST_LOCATION);
+#endif
+#ifdef USE_EINK
+    hiddenFrames.nodelist_lastheard = getBit(mask, FVBIT_NODELIST_LASTHEARD);
+    hiddenFrames.nodelist_hopsignal = getBit(mask, FVBIT_NODELIST_HOPSIGNAL);
+    hiddenFrames.nodelist_distance = getBit(mask, FVBIT_NODELIST_DISTANCE);
+#endif
+#if HAS_GPS
+#ifdef USE_EINK
+    hiddenFrames.nodelist_bearings = getBit(mask, FVBIT_NODELIST_BEARINGS);
+#endif
+    hiddenFrames.gps = getBit(mask, FVBIT_GPS);
+#endif
+    hiddenFrames.lora = getBit(mask, FVBIT_LORA);
+    hiddenFrames.show_favorites = getBit(mask, FVBIT_SHOW_FAVORITES);
+    hiddenFrames.chirpy = getBit(mask, FVBIT_CHIRPY);
+}
+
+void Screen::loadFrameVisibility()
+{
+#ifdef FSCom
+    spiLock->lock();
+    auto file = FSCom.open(frameVisibilityFileName, FILE_O_READ);
+    if (file) {
+        FrameVisFile data{};
+        bool ok = file.read((uint8_t *)&data, sizeof(data)) == sizeof(data) && data.magic == FRAMEVIS_MAGIC &&
+                  data.version == FRAMEVIS_VERSION;
+        file.close();
+        spiLock->unlock();
+        if (ok) {
+            applyHiddenFramesMask(data.mask);
+            LOG_INFO("Loaded frame visibility (mask 0x%08x)", data.mask);
+        } else {
+            LOG_WARN("Frame visibility file invalid, keeping defaults");
+        }
+        return;
+    }
+    spiLock->unlock();
+    LOG_DEBUG("No saved frame visibility, using defaults");
+#endif
+}
+
+void Screen::saveFrameVisibility()
+{
+#ifdef FSCom
+    spiLock->lock();
+    FSCom.mkdir("/prefs");
+    if (FSCom.exists(frameVisibilityFileName))
+        FSCom.remove(frameVisibilityFileName);
+
+    auto file = FSCom.open(frameVisibilityFileName, FILE_O_WRITE);
+    if (file) {
+        FrameVisFile data{};
+        data.magic = FRAMEVIS_MAGIC;
+        data.version = FRAMEVIS_VERSION;
+        data.mask = packHiddenFrames();
+        file.write((uint8_t *)&data, sizeof(data));
+        file.flush();
+        file.close();
+        LOG_INFO("Saved frame visibility (mask 0x%08x)", data.mask);
+    } else {
+        LOG_WARN("Failed to open %s for writing", frameVisibilityFileName);
+    }
+    spiLock->unlock();
+#endif
+}
+
 void Screen::handleStartFirmwareUpdateScreen()
 {
     LOG_DEBUG("Show firmware screen");
@@ -1466,6 +1759,15 @@ void Screen::handleStartFirmwareUpdateScreen()
 
 void Screen::blink()
 {
+#ifdef MESHTASTIC_LOCKDOWN
+    // L4: defensive guard. blink() paints arbitrary geometry, not node
+    // data, so it doesn't actually leak today. But it bypasses the normal
+    // ui->update() path that the lockdown short-circuit gates, so any
+    // future change that puts content into blink would silently leak past
+    // redaction. Refuse to draw when the redaction latch is set.
+    if (meshtastic_security::shouldRedactDisplay())
+        return;
+#endif
     setFastFramerate();
     uint8_t count = 10;
     dispdev->setBrightness(254);

src/graphics/Screen.h

@@ -12,7 +12,21 @@
 #define getStringCenteredX(s) ((SCREEN_WIDTH - display->getStringWidth(s)) / 2)
 namespace graphics
 {
-enum notificationTypeEnum { none, text_banner, selection_picker, node_picker, number_picker, text_input };
+enum notificationTypeEnum {
+    none,
+    text_banner,
+    selection_picker,
+    node_picker,
+    number_picker,
+    hex_picker,
+    text_input,
+    // BLE pairing PIN banner. Treated specially by the lockdown short-circuit
+    // in Screen.cpp: the PIN is ephemeral (regenerated per pair attempt) and
+    // not a real secret, so we allow ui->update() to composite it over the
+    // LOCKED frame. Without this, a first-pair on a locked device cannot
+    // complete because the PIN never renders.
+    pairing_pin,
+};
 
 struct BannerOverlayOptions {
     const char *message;
@@ -623,6 +637,11 @@ class Screen : public concurrency::OSThread
     void toggleFrameVisibility(const std::string &frameName);
     bool isFrameHidden(const std::string &frameName) const;
 
+    // Persist / restore which frames are hidden, across reboots.
+    // Stored as a single uint32 bitmask in /prefs (see Screen.cpp for the format).
+    void loadFrameVisibility();
+    void saveFrameVisibility();
+
 #ifdef USE_EINK
     /// Draw an image to remain on E-Ink display after screen off
     void setScreensaverFrames(FrameCallback einkScreensaver = NULL);
@@ -738,6 +757,11 @@ class Screen : public concurrency::OSThread
         bool chirpy = true;
     } hiddenFrames;
 
+    // Convert hiddenFrames to a uint32 bitmask. Bit positions are fixed per
+    // frame name (see Screen.cpp).
+    uint32_t packHiddenFrames() const;
+    void applyHiddenFramesMask(uint32_t mask);
+
     /// Try to start drawing ASAP
     void setFastFramerate();
 

src/graphics/SharedUIDisplay.cpp

@@ -578,7 +578,11 @@ void drawCommonFooter(OLEDDisplay *display, int16_t x, int16_t y)
 #endif
 
     display->setColor(BLACK);
+#if GRAPHICS_TFT_COLORING_ENABLED
     display->fillRect(0, footerY, SCREEN_WIDTH, footerH);
+#else
+    display->fillRect(0, footerY, connection_icon_width + 1, footerH);
+#endif
     display->setColor(WHITE);
     if (currentResolution == ScreenResolution::High) {
         const int bytesPerRow = (connection_icon_width + 7) / 8;

src/graphics/TFTDisplay.cpp

@@ -1533,8 +1533,7 @@ bool TFTDisplay::hasTouch(void)
 {
 #ifdef RAK14014
     return true;
-#elif !defined(M5STACK) && !defined(HACKADAY_COMMUNICATOR) && !defined(HELTEC_MESH_NODE_T096) &&                                 \
-    !defined(HELTEC_MESH_NODE_T1)
+#elif !defined(M5STACK) && !defined(HACKADAY_COMMUNICATOR) && !defined(HELTEC_MESH_NODE_T096) && !defined(HELTEC_MESH_NODE_T1)
     return tft->touch() != nullptr;
 #else
     return false;
@@ -1553,8 +1552,7 @@ bool TFTDisplay::getTouch(int16_t *x, int16_t *y)
     } else {
         return false;
     }
-#elif !defined(M5STACK) && !defined(HACKADAY_COMMUNICATOR) && !defined(HELTEC_MESH_NODE_T096) &&                                 \
-    !defined(HELTEC_MESH_NODE_T1)
+#elif !defined(M5STACK) && !defined(HACKADAY_COMMUNICATOR) && !defined(HELTEC_MESH_NODE_T096) && !defined(HELTEC_MESH_NODE_T1)
     return tft->getTouch(x, y);
 #else
     return false;

src/graphics/draw/ClockRenderer.cpp

@@ -183,9 +183,13 @@ void drawDigitalClockFrame(OLEDDisplay *display, OLEDDisplayUiState *state, int1
     static float segmentHeight = SEGMENT_HEIGHT * 0.75f;
 
     if (!scaleInitialized) {
+#ifdef DISPLAY_FORCE_SMALL_FONTS
+        float screenwidth_target_ratio = 0.70f; // Target 70% of display width (adjustable)
+#else
         float screenwidth_target_ratio = 0.80f; // Target 80% of display width (adjustable)
-        float max_scale = 3.5f;                 // Safety limit to avoid runaway scaling
-        float step = 0.05f;                     // Step increment per iteration
+#endif
+        float max_scale = 3.5f; // Safety limit to avoid runaway scaling
+        float step = 0.05f;     // Step increment per iteration
 
         float target_width = display->getWidth() * screenwidth_target_ratio;
         float target_height =

src/graphics/draw/MenuHandler.cpp

@@ -126,6 +126,7 @@ void launchReplyForMessage(const StoredMessage &message, bool freetext)
 
 menuHandler::screenMenus menuHandler::menuQueue = MenuNone;
 uint32_t menuHandler::pickedNodeNum = 0;
+meshtastic_Config_LoRaConfig_RegionCode menuHandler::pendingRegion = meshtastic_Config_LoRaConfig_RegionCode_UNSET;
 bool test_enabled = false;
 uint8_t test_count = 0;
 
@@ -174,6 +175,48 @@ void menuHandler::OnboardMessage()
     screen->showOverlayBanner(bannerOptions);
 }
 
+static void applyLoraRegion(meshtastic_Config_LoRaConfig_RegionCode region, bool isHam)
+{
+    config.lora.region = region;
+    config.lora.channel_num = 0; // Reset to default channel
+
+    // Reconcile the preset with the explicitly chosen region: a preset locked to another
+    // region would leave config.lora invalid until applyModemConfig() repairs it with
+    // error/critical-error side effects — or, for the swappable EU trio, the clamp would
+    // flip the region right back. The user picked the region, so the preset follows it.
+    const RegionInfo *newRegion = getRegion(region);
+    if (config.lora.use_preset && !newRegion->supportsPreset(config.lora.modem_preset)) {
+        LOG_INFO("Preset %s not available in %s, using default %s",
+                 DisplayFormatters::getModemPresetDisplayName(config.lora.modem_preset, false, true), newRegion->name,
+                 DisplayFormatters::getModemPresetDisplayName(newRegion->getDefaultPreset(), false, true));
+        config.lora.modem_preset = newRegion->getDefaultPreset();
+    }
+
+    if (isHam && adminModule) {
+        meshtastic_HamParameters hamParams = meshtastic_HamParameters_init_zero;
+        strncpy(hamParams.call_sign, "N0CALL", sizeof(hamParams.call_sign) - 1);
+        strncpy(hamParams.short_name, "N0CL", sizeof(hamParams.short_name));
+        hamParams.tx_power = config.lora.tx_power;
+        hamParams.frequency = config.lora.override_frequency;
+        adminModule->handleSetHamMode(hamParams);
+    }
+    auto changes = SEGMENT_CONFIG;
+#if !(MESHTASTIC_EXCLUDE_PKI_KEYGEN || MESHTASTIC_EXCLUDE_PKI)
+    if (crypto) {
+        crypto->ensurePkiKeys(config.security, owner);
+    }
+#endif
+    initRegion();
+    if (getEffectiveDutyCycle() < 100) {
+        config.lora.ignore_mqtt = true;
+    }
+    if (strncmp(moduleConfig.mqtt.root, default_mqtt_root, strlen(default_mqtt_root)) == 0) {
+        snprintf(moduleConfig.mqtt.root, sizeof(moduleConfig.mqtt.root), "%s/%s", default_mqtt_root, myRegion->name);
+        changes |= SEGMENT_MODULECONFIG;
+    }
+    service->reloadConfig(changes);
+}
+
 void menuHandler::LoraRegionPicker(uint32_t duration)
 {
     static const LoraRegionOption regionOptions[] = {
@@ -209,6 +252,7 @@ void menuHandler::LoraRegionPicker(uint32_t duration)
         {"ITU1_2M (144-146)", OptionsAction::Select, meshtastic_Config_LoRaConfig_RegionCode_ITU1_2M},
         {"ITU2_2M (144-148)", OptionsAction::Select, meshtastic_Config_LoRaConfig_RegionCode_ITU2_2M},
         {"ITU3_2M (144-148)", OptionsAction::Select, meshtastic_Config_LoRaConfig_RegionCode_ITU3_2M},
+        {"ITU2_125CM (220-225)", OptionsAction::Select, meshtastic_Config_LoRaConfig_RegionCode_ITU2_125CM},
 
     };
 
@@ -231,37 +275,34 @@ void menuHandler::LoraRegionPicker(uint32_t duration)
                 return;
             }
 
-            // Guard: without a reboot, reconfigure() applies the region directly.
-            // Reject LORA_24 on sub-GHz-only hardware — getRadio() used to catch this post-reboot.
-            // TODO: change this to either use the validateLoraConfig() logic or at least check the region for wideLora
-            // rather than a hardcoded check for LORA_24.
-            if (selectedRegion == meshtastic_Config_LoRaConfig_RegionCode_LORA_24 &&
-                !(RadioLibInterface::instance && RadioLibInterface::instance->wideLora())) {
-                LOG_WARN("Radio hardware does not support 2.4 GHz; ignoring region selection");
+            // Guard: without a reboot, reconfigure() applies the region directly, so reject
+            // regions this node can't use up front: unrecognized codes, licensed-only regions,
+            // and radio hardware mismatches (2.4 GHz vs sub-GHz) — the same checks the admin
+            // set-config path applies, but side-effect-free: ignoring a menu selection should
+            // not record a critical error or notify clients. getRadio() used to catch hardware
+            // mismatches post-reboot only.
+            auto candidateLora = config.lora;
+            candidateLora.region = selectedRegion;
+            char regionErr[160];
+            if (!RadioInterface::checkConfigRegion(candidateLora, regionErr, sizeof(regionErr))) {
+                LOG_WARN("Ignoring region selection: %s", regionErr);
                 return;
             }
 
-            config.lora.region = selectedRegion;
-            auto changes = SEGMENT_CONFIG;
-
-#if !(MESHTASTIC_EXCLUDE_PKI_KEYGEN || MESHTASTIC_EXCLUDE_PKI)
-            if (crypto) {
-                crypto->ensurePkiKeys(config.security, owner);
+            bool hamMode = getRegion(selectedRegion)->profile->licensedOnly;
+            if (hamMode) {
+                LOG_INFO("User chose an amateur radio mode region");
+                pendingRegion = selectedRegion;
+                menuQueue = HamModeConfirm;
+                screen->runNow();
+            } else if (owner.is_licensed) {
+                LOG_INFO("Licensed user chose a non-ham region; prompting to revert licensed mode");
+                pendingRegion = selectedRegion;
+                menuQueue = LicensedToNormalConfirm;
+                screen->runNow();
+            } else {
+                applyLoraRegion(selectedRegion, false);
             }
-#endif
-            config.lora.tx_enabled = true;
-            initRegion();
-            if (getEffectiveDutyCycle() < 100) {
-                config.lora.ignore_mqtt = true; // Ignore MQTT by default if region has a duty cycle limit
-            }
-
-            if (strncmp(moduleConfig.mqtt.root, default_mqtt_root, strlen(default_mqtt_root)) == 0) {
-                //  Default broker is in use, so subscribe to the appropriate MQTT root topic for this region
-                sprintf(moduleConfig.mqtt.root, "%s/%s", default_mqtt_root, myRegion->name);
-                changes |= SEGMENT_MODULECONFIG;
-            }
-
-            service->reloadConfig(changes);
         });
 
     bannerOptions.durationMs = duration;
@@ -278,6 +319,38 @@ void menuHandler::LoraRegionPicker(uint32_t duration)
     screen->showOverlayBanner(bannerOptions);
 }
 
+void menuHandler::hamModeConfirmMenu()
+{
+    static const char *confirmOptions[] = {"No", "Yes"};
+    BannerOverlayOptions confirmBanner;
+    confirmBanner.message = "I confirm I am a\nlicensed amateur\nradio operator";
+    confirmBanner.optionsArrayPtr = confirmOptions;
+    confirmBanner.optionsCount = 2;
+    confirmBanner.bannerCallback = [](int selected) {
+        if (selected == 1)
+            applyLoraRegion(pendingRegion, true);
+    };
+    screen->showOverlayBanner(confirmBanner);
+}
+
+void menuHandler::licensedToNormalConfirmMenu()
+{
+    static const char *confirmOptions[] = {"Keep licensed", "Revert to Normal"};
+    BannerOverlayOptions confirmBanner;
+    confirmBanner.message = "Revert licensed\nmode? This will\nre-enable encryption.";
+    confirmBanner.optionsArrayPtr = confirmOptions;
+    confirmBanner.optionsCount = 2;
+    confirmBanner.bannerCallback = [](int selected) {
+        if (selected == 1) {
+            owner.is_licensed = false;
+            config.lora.override_duty_cycle = false;
+            service->reloadOwner(false);
+        }
+        applyLoraRegion(pendingRegion, false);
+    };
+    screen->showOverlayBanner(confirmBanner);
+}
+
 void menuHandler::deviceRolePicker()
 {
     static const char *optionsArray[] = {"Back", "Client", "Client Mute", "Lost and Found", "Tracker"};
@@ -1499,6 +1572,7 @@ void menuHandler::manageNodeMenu()
                 nodeDB->set_favorite(false, menuHandler::pickedNodeNum);
             } else {
                 LOG_INFO("Adding node %08X to favorites", menuHandler::pickedNodeNum);
+                // set_favorite() already logs PROTECTED_CAP_WARN_FMT on a cap refusal; don't double-log here.
                 nodeDB->set_favorite(true, menuHandler::pickedNodeNum);
             }
             screen->setFrames(graphics::Screen::FOCUS_PRESERVE);
@@ -1542,15 +1616,23 @@ void menuHandler::manageNodeMenu()
                 return;
             }
 
+            bool changed = false;
             if (nodeInfoLiteIsIgnored(n)) {
                 nodeInfoLiteSetBit(n, NODEINFO_BITFIELD_IS_IGNORED_MASK, false);
                 LOG_INFO("Unignoring node %08X", menuHandler::pickedNodeNum);
-            } else {
-                nodeInfoLiteSetBit(n, NODEINFO_BITFIELD_IS_IGNORED_MASK, true);
+                changed = true;
+            } else if (nodeDB->setProtectedFlag(n, NODEINFO_BITFIELD_IS_IGNORED_MASK, true)) {
                 LOG_INFO("Ignoring node %08X", menuHandler::pickedNodeNum);
+                changed = true;
+            } else {
+                LOG_WARN(NodeDB::PROTECTED_CAP_WARN_FMT, "ignore", menuHandler::pickedNodeNum, MAX_NUM_NODES - 2);
+            }
+            // Only persist/notify when the ignore bit actually moved; a cap
+            // refusal changed nothing and shouldn't trigger a prefs save.
+            if (changed) {
+                nodeDB->notifyObservers(true);
+                nodeDB->saveToDisk();
             }
-            nodeDB->notifyObservers(true);
-            nodeDB->saveToDisk();
             screen->setFrames(graphics::Screen::FOCUS_PRESERVE);
             return;
         }
@@ -2821,6 +2903,12 @@ void menuHandler::handleMenuSwitch(OLEDDisplay *display)
     case ThemeMenu:
         themeMenu();
         break;
+    case HamModeConfirm:
+        hamModeConfirmMenu();
+        break;
+    case LicensedToNormalConfirm:
+        licensedToNormalConfirmMenu();
+        break;
     }
     menuQueue = MenuNone;
 }

src/graphics/draw/MenuHandler.h

@@ -55,10 +55,13 @@ class menuHandler
         FrameToggles,
         DisplayUnits,
         MessageBubblesMenu,
-        ThemeMenu
+        ThemeMenu,
+        HamModeConfirm,
+        LicensedToNormalConfirm
     };
     static screenMenus menuQueue;
     static uint32_t pickedNodeNum; // node selected by NodePicker for ManageNodeMenu
+    static meshtastic_Config_LoRaConfig_RegionCode pendingRegion;
 
     static void OnboardMessage();
     static void LoraRegionPicker(uint32_t duration = 30000);
@@ -111,6 +114,8 @@ class menuHandler
     static void messageBubblesMenu();
     static void themeMenu();
     static void textMessageMenu();
+    static void hamModeConfirmMenu();
+    static void licensedToNormalConfirmMenu();
 
   private:
     static void saveUIConfig();

src/graphics/draw/NotificationRenderer.cpp

@@ -66,6 +66,15 @@ uint32_t pow_of_10(uint32_t n)
     return ret;
 }
 
+uint64_t pow_of_16(uint32_t n)
+{
+    uint64_t ret = 1;
+    for (uint32_t i = 0; i < n; i++) {
+        ret *= 16ULL;
+    }
+    return ret;
+}
+
 char graphics::NotificationRenderer::alertBannerLines[MAX_LINES + 1][64] = {};
 uint8_t graphics::NotificationRenderer::alertBannerLineCount = 0;
 graphics::NotificationRenderer::BannerFont graphics::NotificationRenderer::alertBannerLineFonts[MAX_LINES + 1] = {};
@@ -251,6 +260,12 @@ void NotificationRenderer::drawBannercallback(OLEDDisplay *display, OLEDDisplayU
         break;
     case notificationTypeEnum::text_banner:
     case notificationTypeEnum::selection_picker:
+    case notificationTypeEnum::pairing_pin:
+        // pairing_pin is rendered the same as text_banner — it's just a
+        // text banner. The split type exists only so the lockdown UI
+        // short-circuit in Screen.cpp can recognise the BLE pair-PIN
+        // banner as the one safe banner to composite over the LOCKED
+        // frame.
         drawAlertBannerOverlay(display, state);
         break;
     case notificationTypeEnum::node_picker:
@@ -259,6 +274,9 @@ void NotificationRenderer::drawBannercallback(OLEDDisplay *display, OLEDDisplayU
     case notificationTypeEnum::number_picker:
         drawNumberPicker(display, state);
         break;
+    case notificationTypeEnum::hex_picker:
+        drawHexPicker(display, state);
+        break;
     }
 }
 
@@ -345,6 +363,105 @@ void NotificationRenderer::drawNumberPicker(OLEDDisplay *display, OLEDDisplayUiS
     drawNotificationBox(display, state, linePointers, totalLines, 0);
 }
 
+void NotificationRenderer::drawHexPicker(OLEDDisplay *display, OLEDDisplayUiState *state)
+{
+    const char *lineStarts[MAX_LINES + 1] = {0};
+    uint16_t lineCount = 0;
+
+    // Parse lines
+    char *alertEnd = alertBannerMessage + strnlen(alertBannerMessage, sizeof(alertBannerMessage));
+    lineStarts[lineCount] = alertBannerMessage;
+
+    // Find lines
+    while ((lineCount < MAX_LINES) && (lineStarts[lineCount] < alertEnd)) {
+        lineStarts[lineCount + 1] = std::find((char *)lineStarts[lineCount], alertEnd, '\n');
+        if (lineStarts[lineCount + 1][0] == '\n')
+            lineStarts[lineCount + 1] += 1;
+        lineCount++;
+    }
+    // modulo to extract
+    uint8_t this_digit = (currentNumber % (pow_of_16(numDigits - curSelected))) / (pow_of_16(numDigits - curSelected - 1));
+    // Handle input
+    if (inEvent.inputEvent == INPUT_BROKER_UP || inEvent.inputEvent == INPUT_BROKER_ALT_PRESS ||
+        inEvent.inputEvent == INPUT_BROKER_UP_LONG) {
+        if (this_digit == 15) {
+            currentNumber -= 15 * (pow_of_16(numDigits - curSelected - 1));
+        } else {
+            currentNumber += (pow_of_16(numDigits - curSelected - 1));
+        }
+    } else if (inEvent.inputEvent == INPUT_BROKER_DOWN || inEvent.inputEvent == INPUT_BROKER_USER_PRESS ||
+               inEvent.inputEvent == INPUT_BROKER_DOWN_LONG) {
+        if (this_digit == 0) {
+            currentNumber += 15 * (pow_of_16(numDigits - curSelected - 1));
+        } else {
+            currentNumber -= (pow_of_16(numDigits - curSelected - 1));
+        }
+    } else if (inEvent.inputEvent == INPUT_BROKER_ANYKEY) {
+        if (inEvent.kbchar > 47 && inEvent.kbchar < 58) { // have a digit
+            currentNumber -= this_digit * (pow_of_16(numDigits - curSelected - 1));
+            currentNumber += (inEvent.kbchar - 48) * (pow_of_16(numDigits - curSelected - 1));
+            curSelected++;
+        }
+    } else if (inEvent.inputEvent == INPUT_BROKER_SELECT || inEvent.inputEvent == INPUT_BROKER_RIGHT) {
+        curSelected++;
+    } else if (inEvent.inputEvent == INPUT_BROKER_LEFT) {
+        curSelected--;
+    } else if ((inEvent.inputEvent == INPUT_BROKER_CANCEL || inEvent.inputEvent == INPUT_BROKER_ALT_LONG) &&
+               alertBannerUntil != 0) {
+        resetBanner();
+        return;
+    }
+    if (curSelected == static_cast<int8_t>(numDigits)) {
+        alertBannerCallback(currentNumber);
+        resetBanner();
+        return;
+    }
+
+    inEvent.inputEvent = INPUT_BROKER_NONE;
+    if (alertBannerMessage[0] == '\0')
+        return;
+
+    uint16_t totalLines = lineCount + 2;
+    const char *linePointers[totalLines + 1] = {0}; // this is sort of a dynamic allocation
+
+    // copy the linestarts to display to the linePointers holder
+    for (uint16_t i = 0; i < lineCount; i++) {
+        linePointers[i] = lineStarts[i];
+    }
+    std::string digits = " ";
+    std::string arrowPointer = " ";
+    for (uint16_t i = 0; i < numDigits; i++) {
+        // Modulo minus modulo to return just the current number
+        uint8_t digitValue = (currentNumber % (pow_of_16(numDigits - i))) / (pow_of_16(numDigits - i - 1));
+        if (digitValue < 10) {
+            digits += std::to_string(digitValue) + " ";
+        } else if (digitValue == 10) {
+            digits += "A ";
+        } else if (digitValue == 11) {
+            digits += "B ";
+        } else if (digitValue == 12) {
+            digits += "C ";
+        } else if (digitValue == 13) {
+            digits += "D ";
+        } else if (digitValue == 14) {
+            digits += "E ";
+        } else if (digitValue == 15) {
+            digits += "F ";
+        }
+
+        if (curSelected == i) {
+            arrowPointer += "^ ";
+        } else {
+            arrowPointer += "_ ";
+        }
+    }
+
+    linePointers[lineCount++] = digits.c_str();
+    linePointers[lineCount++] = arrowPointer.c_str();
+
+    drawNotificationBox(display, state, linePointers, totalLines, 0);
+}
+
 void NotificationRenderer::drawNodePicker(OLEDDisplay *display, OLEDDisplayUiState *state)
 {
     static uint32_t selectedNodenum = 0;

src/graphics/draw/NotificationRenderer.h

@@ -42,6 +42,7 @@ class NotificationRenderer
     static void drawBannercallback(OLEDDisplay *display, OLEDDisplayUiState *state);
     static void drawAlertBannerOverlay(OLEDDisplay *display, OLEDDisplayUiState *state);
     static void drawNumberPicker(OLEDDisplay *display, OLEDDisplayUiState *state);
+    static void drawHexPicker(OLEDDisplay *display, OLEDDisplayUiState *state);
     static void drawNodePicker(OLEDDisplay *display, OLEDDisplayUiState *state);
     static void drawTextInput(OLEDDisplay *display, OLEDDisplayUiState *state);
     static void drawNotificationBox(OLEDDisplay *display, OLEDDisplayUiState *state, const char *lines[MAX_LINES + 1],

src/graphics/draw/UIRenderer.cpp

@@ -79,10 +79,12 @@ static inline void transformNeedlePoint(float localX, float localY, float sinHea
     outY = static_cast<int16_t>(y);
 }
 
+#if GRAPHICS_TFT_COLORING_ENABLED
 static float getCompassRingAngleOffset(float heading)
 {
     return (uiconfig.compass_mode != meshtastic_CompassMode_FIXED_RING) ? -heading : 0.0f;
 }
+#endif
 
 static inline StandardCompassNeedlePoints computeStandardCompassNeedlePoints(int16_t compassX, int16_t compassY,
                                                                              uint16_t compassDiam, float headingRadian,
@@ -1142,11 +1144,16 @@ void UIRenderer::drawDeviceFocused(OLEDDisplay *display, OLEDDisplayUiState *sta
     bool origBold = config.display.heading_bold;
     config.display.heading_bold = false;
 
-    // Display Region and Channel Utilization
-    if (currentResolution == ScreenResolution::UltraLow) {
-        drawNodes(display, x, getTextPositions(display)[line] + 2, nodeStatus, -1, false, "online");
+    if (!config.lora.tx_enabled) {
+        const char *txdisabled = "Transmit Disabled";
+        display->drawString(x, getTextPositions(display)[line], txdisabled);
     } else {
-        drawNodes(display, x + 1, getTextPositions(display)[line] + 2, nodeStatus, -1, false, "online");
+        // Display Region and Channel Utilization
+        if (currentResolution == ScreenResolution::UltraLow) {
+            drawNodes(display, x, getTextPositions(display)[line] + 2, nodeStatus, -1, false, "online");
+        } else {
+            drawNodes(display, x + 1, getTextPositions(display)[line] + 2, nodeStatus, -1, false, "online");
+        }
     }
     char uptimeStr[32] = "";
     if (currentResolution != ScreenResolution::UltraLow) {

src/graphics/niche/InkHUD/Applets/System/Menu/MenuAction.h

@@ -69,6 +69,7 @@ enum MenuAction {
     SET_REGION_ITU1_2M,
     SET_REGION_ITU2_2M,
     SET_REGION_ITU3_2M,
+    SET_REGION_ITU2_125CM,
     // Device Roles
     SET_ROLE_CLIENT,
     SET_ROLE_CLIENT_MUTE,
@@ -128,6 +129,7 @@ enum MenuAction {
     // Administration
     RESET_NODEDB_ALL,
     RESET_NODEDB_KEEP_FAVORITES,
+    WIPE_MESSAGES_ALL,
 };
 
 } // namespace NicheGraphics::InkHUD

src/graphics/niche/InkHUD/Applets/System/Menu/MenuApplet.cpp

@@ -6,6 +6,7 @@
 #include "GPS.h"
 #include "MeshRadio.h"
 #include "MeshService.h"
+#include "MessageStore.h"
 #include "RTC.h"
 #include "Router.h"
 #include "airtime.h"
@@ -287,7 +288,7 @@ static void applyLoRaRegion(meshtastic_Config_LoRaConfig_RegionCode region)
     }
 
     if (strncmp(moduleConfig.mqtt.root, default_mqtt_root, strlen(default_mqtt_root)) == 0) {
-        sprintf(moduleConfig.mqtt.root, "%s/%s", default_mqtt_root, myRegion->name);
+        snprintf(moduleConfig.mqtt.root, sizeof(moduleConfig.mqtt.root), "%s/%s", default_mqtt_root, myRegion->name);
         changes |= SEGMENT_MODULECONFIG;
     }
     // Notify UI that changes are being applied
@@ -796,6 +797,10 @@ void InkHUD::MenuApplet::execute(MenuItem item)
         applyLoRaRegion(meshtastic_Config_LoRaConfig_RegionCode_ITU3_2M);
         break;
 
+    case SET_REGION_ITU2_125CM:
+        applyLoRaRegion(meshtastic_Config_LoRaConfig_RegionCode_ITU2_125CM);
+        break;
+
     // Roles
     case SET_ROLE_CLIENT:
         applyDeviceRole(meshtastic_Config_DeviceConfig_Role_CLIENT);
@@ -1009,6 +1014,13 @@ void InkHUD::MenuApplet::execute(MenuItem item)
         rebootAtMsec = millis() + DEFAULT_REBOOT_SECONDS * 1000;
         break;
 
+    case WIPE_MESSAGES_ALL:
+        LOG_INFO("Wiping all messages from menu");
+        messageStore.clearAllMessages();
+        inkhud->persistence->loadLatestMessage();
+        inkhud->forceUpdate(Drivers::EInk::UpdateTypes::FULL, true);
+        break;
+
     default:
         LOG_WARN("Action not implemented");
     }
@@ -1126,6 +1138,7 @@ void InkHUD::MenuApplet::showPage(MenuPage page)
         // Administration Section
         items.push_back(MenuItem::Header("Administration"));
         items.push_back(MenuItem("Reset NodeDB", MenuPage::NODE_CONFIG_ADMIN_RESET));
+        items.push_back(MenuItem("Wipe Messages", MenuPage::NODE_CONFIG_ADMIN_MESSAGES));
 
         // Exit
         items.push_back(MenuItem("Exit", MenuPage::EXIT));
@@ -1500,6 +1513,7 @@ void InkHUD::MenuApplet::showPage(MenuPage page)
         items.push_back(MenuItem("ITU1_2M (144-146)", MenuAction::SET_REGION_ITU1_2M, MenuPage::EXIT));
         items.push_back(MenuItem("ITU2_2M (144-148)", MenuAction::SET_REGION_ITU2_2M, MenuPage::EXIT));
         items.push_back(MenuItem("ITU3_2M (144-148)", MenuAction::SET_REGION_ITU3_2M, MenuPage::EXIT));
+        items.push_back(MenuItem("ITU2_125CM (220-225)", MenuAction::SET_REGION_ITU2_125CM, MenuPage::EXIT));
         items.push_back(MenuItem("Exit", MenuPage::EXIT));
         break;
 
@@ -1529,6 +1543,13 @@ void InkHUD::MenuApplet::showPage(MenuPage page)
         items.push_back(MenuItem("Exit", MenuPage::EXIT));
         break;
 
+    case NODE_CONFIG_ADMIN_MESSAGES:
+        previousPage = MenuPage::NODE_CONFIG;
+        items.push_back(MenuItem("Back", previousPage));
+        items.push_back(MenuItem("Wipe All Messages", MenuAction::WIPE_MESSAGES_ALL, MenuPage::EXIT));
+        items.push_back(MenuItem("Exit", MenuPage::EXIT));
+        break;
+
     // Exit
     case EXIT:
         sendToBackground(); // Menu applet dismissed, allow normal behavior to resume

src/graphics/niche/InkHUD/Applets/System/Menu/MenuPage.h

@@ -36,6 +36,7 @@ enum MenuPage : uint8_t {
     NODE_CONFIG_BLUETOOTH,
     NODE_CONFIG_POSITION,
     NODE_CONFIG_ADMIN_RESET,
+    NODE_CONFIG_ADMIN_MESSAGES,
     TIMEZONE,
     APPLETS,
     AUTOSHOW,

src/graphics/niche/InkHUD/Applets/System/Notification/NotificationApplet.cpp

@@ -3,6 +3,7 @@
 #include "./NotificationApplet.h"
 
 #include "./Notification.h"
+#include "MessageStore.h"
 #include "graphics/niche/InkHUD/Persistence.h"
 
 #include "meshUtils.h"
@@ -231,7 +232,7 @@ std::string InkHUD::NotificationApplet::getNotificationText(uint16_t widthAvaila
         bool msgIsBroadcast = currentNotification.type == Notification::Type::NOTIFICATION_MESSAGE_BROADCAST;
 
         // Pick source of message
-        const MessageStore::Message *message =
+        const StoredMessage *message =
             msgIsBroadcast ? &inkhud->persistence->latestMessage.broadcast : &inkhud->persistence->latestMessage.dm;
 
         // Find info about the sender
@@ -261,7 +262,7 @@ std::string InkHUD::NotificationApplet::getNotificationText(uint16_t widthAvaila
                 text += hexifyNodeNum(message->sender);
 
             text += ": ";
-            text += message->text;
+            text += MessageStore::getText(*message);
         }
     }
 

src/graphics/niche/InkHUD/Applets/User/AllMessage/AllMessageApplet.cpp

@@ -2,6 +2,8 @@
 
 #include "./AllMessageApplet.h"
 
+#include "MessageStore.h"
+
 using namespace NicheGraphics;
 
 void InkHUD::AllMessageApplet::onActivate()
@@ -37,7 +39,7 @@ int InkHUD::AllMessageApplet::onReceiveTextMessage(const meshtastic_MeshPacket *
 void InkHUD::AllMessageApplet::onRender(bool full)
 {
     // Find newest message, regardless of whether DM or broadcast
-    MessageStore::Message *message;
+    StoredMessage *message;
     if (latestMessage->wasBroadcast)
         message = &latestMessage->broadcast;
     else
@@ -96,7 +98,7 @@ void InkHUD::AllMessageApplet::onRender(bool full)
     // ===================
 
     // Parse any non-ascii chars in the message
-    std::string text = parse(message->text);
+    std::string text = parse(std::string(MessageStore::getText(*message)));
 
     // Extra gap below the header
     int16_t textTop = headerDivY + padDivH;

src/graphics/niche/InkHUD/Applets/User/DM/DMApplet.cpp

@@ -2,6 +2,8 @@
 
 #include "./DMApplet.h"
 
+#include "MessageStore.h"
+
 using namespace NicheGraphics;
 
 void InkHUD::DMApplet::onActivate()
@@ -92,7 +94,7 @@ void InkHUD::DMApplet::onRender(bool full)
     // ===================
 
     // Parse any non-ascii chars in the message
-    std::string text = parse(latestMessage->dm.text);
+    std::string text = parse(std::string(MessageStore::getText(latestMessage->dm)));
 
     // Extra gap below the header
     int16_t textTop = headerDivY + padDivH;

src/graphics/niche/InkHUD/Applets/User/ThreadedMessage/ThreadedMessageApplet.cpp

@@ -7,19 +7,9 @@
 
 using namespace NicheGraphics;
 
-// Hard limits on how much message data to write to flash
-// Avoid filling the storage if something goes wrong
-// Normal usage should be well below this size
-constexpr uint8_t MAX_MESSAGES_SAVED = 10;
-constexpr uint32_t MAX_MESSAGE_SIZE = 250;
-
 InkHUD::ThreadedMessageApplet::ThreadedMessageApplet(uint8_t channelIndex)
     : SinglePortModule("ThreadedMessageApplet", meshtastic_PortNum_TEXT_MESSAGE_APP), channelIndex(channelIndex)
 {
-    // Create the message store
-    // Will shortly attempt to load messages from RAM, if applet is active
-    // Label (filename in flash) is set from channel index
-    store = new MessageStore("ch" + to_string(channelIndex));
 }
 
 void InkHUD::ThreadedMessageApplet::onRender(bool full)
@@ -61,17 +51,24 @@ void InkHUD::ThreadedMessageApplet::onRender(bool full)
     const uint16_t msgW = (msgR - msgL) + 1;
 
     int16_t msgB = height() - 1; // Vertical cursor for drawing. Messages are bottom-aligned to this value.
-    uint8_t i = 0;               // Index of stored message
 
-    // Loop over messages
-    // - until no messages left, or
-    // - until no part of message fits on screen
-    while (msgB >= (0 - fontSmall.lineHeight()) && i < store->messages.size()) {
+    // Iterate the global store newest-first, showing only broadcast messages on our channel
+    const auto &allMessages = messageStore.getLiveMessages();
+    int msgIdx = (int)allMessages.size() - 1;
+
+    while (msgB >= (0 - fontSmall.lineHeight()) && msgIdx >= 0) {
+
+        const StoredMessage &m = allMessages.at(msgIdx);
+
+        // Skip messages that don't belong to this channel or are DMs
+        if (m.type != MessageType::BROADCAST || m.channelIndex != channelIndex) {
+            msgIdx--;
+            continue;
+        }
 
         // Grab data for message
-        const MessageStore::Message &m = store->messages.at(i);
-        bool outgoing = (m.sender == 0) || (m.sender == myNodeInfo.my_node_num); // Own NodeNum if canned message
-        std::string bodyText = parse(m.text);                                    // Parse any non-ascii chars in the message
+        bool outgoing = (m.sender == myNodeInfo.my_node_num);
+        std::string bodyText = parse(std::string(MessageStore::getText(m))); // Parse any non-ascii chars
 
         // Cache bottom Y of message text
         // - Used when drawing vertical line alongside
@@ -152,18 +149,13 @@ void InkHUD::ThreadedMessageApplet::onRender(bool full)
         // Move cursor up: padding before next message
         msgB -= fontSmall.lineHeight() * 0.5;
 
-        i++;
+        msgIdx--;
     } // End of loop: drawing each message
 
     // Fade effect:
     // Area immediately below the divider. Overdraw with sparse white lines.
     // Make text appear to pass behind the header
     hatchRegion(0, dividerY + 1, width(), fontSmall.lineHeight() / 3, 2, WHITE);
-
-    // If we've run out of screen to draw messages, we can drop any leftover data from the queue
-    // Those messages have been pushed off the screen-top by newer ones
-    while (i < store->messages.size())
-        store->messages.pop_back();
 }
 
 // Code which runs when the applet begins running
@@ -198,16 +190,8 @@ ProcessMessage InkHUD::ThreadedMessageApplet::handleReceived(const meshtastic_Me
     if (mp.to != NODENUM_BROADCAST)
         return ProcessMessage::CONTINUE;
 
-    // Extract info into our slimmed-down "StoredMessage" type
-    MessageStore::Message newMessage;
-    newMessage.timestamp = getValidTime(RTCQuality::RTCQualityDevice, true); // Current RTC time
-    newMessage.sender = mp.from;
-    newMessage.channelIndex = mp.channel;
-    newMessage.text = std::string((const char *)mp.decoded.payload.bytes, mp.decoded.payload.size);
-
-    // Store newest message at front
-    // These records are used when rendering, and also stored in flash at shutdown
-    store->messages.push_front(newMessage);
+    // Store in the global messageStore — this handles sender, timestamp, channel, text, and ack status
+    messageStore.addFromPacket(mp);
 
     // If this was an incoming message, suggest that our applet becomes foreground, if permitted
     if (getFrom(&mp) != nodeDB->getNodeNum())
@@ -232,37 +216,25 @@ bool InkHUD::ThreadedMessageApplet::approveNotification(Notification &n)
         return true;
 }
 
-// Save several recent messages to flash
-// Stores the contents of ThreadedMessageApplet::messages
-// Just enough messages to fill the display
-// Messages are packed "back-to-back", to minimize blocks of flash used
+// Save messages to flash via the global messageStore.
+// The global store holds messages for all channels; no per-channel file is needed.
 void InkHUD::ThreadedMessageApplet::saveMessagesToFlash()
 {
-    // Create a label (will become the filename in flash)
-    std::string label = "ch" + to_string(channelIndex);
-
-    store->saveToFlash();
+    messageStore.saveToFlash();
 }
 
-// Load recent messages to flash
-// Fills ThreadedMessageApplet::messages with previous messages
-// Just enough messages have been stored to cover the display
+// Messages are loaded once by InkHUD::begin() before applets start.
+// Nothing to do here at per-applet activation time.
 void InkHUD::ThreadedMessageApplet::loadMessagesFromFlash()
 {
-    // Create a label (will become the filename in flash)
-    std::string label = "ch" + to_string(channelIndex);
-
-    store->loadFromFlash();
+    // No-op: messageStore.loadFromFlash() is called in InkHUD::begin()
 }
 
 // Code to run when device is shutting down
 // This is in addition to any onDeactivate() code, which will also run
-// Todo: implement before a reboot also
 void InkHUD::ThreadedMessageApplet::onShutdown()
 {
-    // Save our current set of messages to flash, provided the applet isn't disabled
-    if (isActive())
-        saveMessagesToFlash();
+    // messageStore.saveToFlash() is called centrally by Events::beforeDeepSleep / beforeReboot
 }
 
-#endif
+#endif

src/graphics/niche/InkHUD/Applets/User/ThreadedMessage/ThreadedMessageApplet.h

@@ -20,8 +20,8 @@ Suggest a max of two channel, to minimize fs usage?
 
 #include "configuration.h"
 
+#include "MessageStore.h"
 #include "graphics/niche/InkHUD/Applet.h"
-#include "graphics/niche/InkHUD/MessageStore.h"
 
 #include "modules/TextMessageModule.h"
 
@@ -49,7 +49,6 @@ class ThreadedMessageApplet : public Applet, public SinglePortModule
     void saveMessagesToFlash();
     void loadMessagesFromFlash();
 
-    MessageStore *store; // Messages, held in RAM for use, ready to save to flash on shutdown
     uint8_t channelIndex = 0;
 };
 

src/graphics/niche/InkHUD/Events.cpp

@@ -2,6 +2,7 @@
 
 #include "./Events.h"
 
+#include "MessageStore.h"
 #include "PowerFSM.h"
 #include "RTC.h"
 #include "buzz.h"
@@ -514,6 +515,7 @@ int InkHUD::Events::beforeReboot(void *unused)
         inkhud->persistence->saveLatestMessage();
     } else {
         NicheGraphics::clearFlashData();
+        messageStore.clearAllMessages(); // also wipe the shared message store
     }
 
     // Note: no forceUpdate call here
@@ -532,32 +534,27 @@ int InkHUD::Events::onReceiveTextMessage(const meshtastic_MeshPacket *packet)
     if (getFrom(packet) == nodeDB->getNodeNum())
         return 0;
 
-    // Determine whether the message is broadcast or a DM
-    // Store this info to prevent confusion after a reboot
-    // Avoids need to compare timestamps, because of situation where "future" messages block newly received, if time not set
-    inkhud->persistence->latestMessage.wasBroadcast = isBroadcast(packet->to);
+    bool isBroadcastMsg = isBroadcast(packet->to);
+    inkhud->persistence->latestMessage.wasBroadcast = isBroadcastMsg;
 
-    // Pick the appropriate variable to store the message in
-    MessageStore::Message *storedMessage = inkhud->persistence->latestMessage.wasBroadcast
-                                               ? &inkhud->persistence->latestMessage.broadcast
-                                               : &inkhud->persistence->latestMessage.dm;
-
-    // Store nodenum of the sender
-    // Applets can use this to fetch user data from nodedb, if they want
-    storedMessage->sender = packet->from;
-
-    // Store the time (epoch seconds) when message received
-    storedMessage->timestamp = getValidTime(RTCQuality::RTCQualityDevice, true); // Current RTC time
-
-    // Store the channel
-    // - (potentially) used to determine whether notification shows
-    // - (potentially) used to determine which applet to focus
-    storedMessage->channelIndex = packet->channel;
-
-    // Store the text
-    // Need to specify manually how many bytes, because source not null-terminated
-    storedMessage->text =
-        std::string(&packet->decoded.payload.bytes[0], &packet->decoded.payload.bytes[packet->decoded.payload.size]);
+    if (!isBroadcastMsg) {
+        // DMs never pass through ThreadedMessageApplet, so add them to the global store here
+        // so they survive reboots. Derive the latestMessage cache entry from the stored result.
+        inkhud->persistence->latestMessage.dm = messageStore.addFromPacket(*packet);
+    } else {
+        // Broadcasts are added to the global store by ThreadedMessageApplet::handleReceived().
+        // Here we only update the latestMessage cache used by AllMessageApplet / NotificationApplet.
+        StoredMessage &sm = inkhud->persistence->latestMessage.broadcast;
+        sm.sender = packet->from;
+        sm.timestamp = getValidTime(RTCQuality::RTCQualityDevice, true);
+        sm.channelIndex = packet->channel;
+        const char *payload = reinterpret_cast<const char *>(packet->decoded.payload.bytes);
+        size_t storedLen = packet->decoded.payload.size;
+        if (storedLen >= MAX_MESSAGE_SIZE)
+            storedLen = MAX_MESSAGE_SIZE - 1;
+        sm.textOffset = MessageStore::storeText(payload, storedLen);
+        sm.textLength = static_cast<uint16_t>(storedLen);
+    }
 
     return 0; // Tell caller to continue notifying other observers. (No reason to abort this event)
 }

src/graphics/niche/InkHUD/InkHUD.cpp

@@ -9,6 +9,10 @@
 #include "./SystemApplet.h"
 #include "./Tile.h"
 #include "./WindowManager.h"
+#include "FSCommon.h"
+#include "MessageStore.h"
+#include "SPILock.h"
+#include "concurrency/LockGuard.h"
 
 using namespace NicheGraphics;
 
@@ -60,11 +64,102 @@ void InkHUD::InkHUD::notifyApplyingChanges()
     }
 }
 
+// One-time migration from the old per-channel InkHUD message files (/NicheGraphics/ch*.msgs)
+// to the firmware-wide MessageStore format (/Messages_default.msgs).
+// Only runs when the new store loaded empty, meaning this is the first boot after the format change.
+// Old files are deleted once migrated.
+static void migrateOldInkHUDMessages()
+{
+#ifdef FSCom
+    bool migrated = false;
+    constexpr uint8_t MAX_CHANNELS = 8;
+    constexpr uint32_t OLD_MAX_MSG_SIZE = 250;
+
+    for (uint8_t ch = 0; ch < MAX_CHANNELS; ch++) {
+        std::string path = "/NicheGraphics/ch";
+        path += std::to_string(ch);
+        path += ".msgs";
+
+        spiLock->lock();
+        bool exists = FSCom.exists(path.c_str());
+        spiLock->unlock();
+        if (!exists)
+            continue;
+
+        concurrency::LockGuard guard(spiLock);
+
+        auto f = FSCom.open(path.c_str(), FILE_O_READ);
+        if (!f || f.size() == 0) {
+            if (f)
+                f.close();
+            FSCom.remove(path.c_str());
+            continue;
+        }
+
+        uint8_t count = 0;
+        f.readBytes(reinterpret_cast<char *>(&count), 1);
+
+        std::vector<StoredMessage> channelMsgs;
+        for (uint8_t i = 0; i < count; i++) {
+            StoredMessage sm;
+            f.readBytes(reinterpret_cast<char *>(&sm.timestamp), sizeof(sm.timestamp));
+            f.readBytes(reinterpret_cast<char *>(&sm.sender), sizeof(sm.sender));
+            f.readBytes(reinterpret_cast<char *>(&sm.channelIndex), sizeof(sm.channelIndex));
+
+            char textBuf[OLD_MAX_MSG_SIZE + 1] = {};
+            uint32_t textLen = 0;
+            char c;
+            while (textLen < OLD_MAX_MSG_SIZE) {
+                if (f.readBytes(&c, 1) != 1)
+                    break;
+                if (c == '\0')
+                    break;
+                textBuf[textLen++] = c;
+            }
+
+            sm.dest = NODENUM_BROADCAST;
+            sm.type = MessageType::BROADCAST;
+            sm.isBootRelative = false;
+            sm.ackStatus = AckStatus::ACKED;
+            size_t storedLen = (textLen >= MAX_MESSAGE_SIZE) ? MAX_MESSAGE_SIZE - 1 : textLen;
+            sm.textOffset = MessageStore::storeText(textBuf, storedLen);
+            sm.textLength = static_cast<uint16_t>(storedLen);
+
+            channelMsgs.push_back(sm);
+        }
+
+        // Old format stored newest-first (push_front); insert oldest-first for correct chronological order
+        for (int i = static_cast<int>(channelMsgs.size()) - 1; i >= 0; i--)
+            messageStore.addLiveMessage(channelMsgs[i]);
+        if (!channelMsgs.empty())
+            migrated = true;
+
+        f.close();
+        FSCom.remove(path.c_str());
+        LOG_INFO("Migrated %u messages from %s", static_cast<uint32_t>(count), path.c_str());
+    }
+
+    // Delete the old latest.msgs; the latestMessage cache will be re-derived from migrated channel messages
+    spiLock->lock();
+    if (FSCom.exists("/NicheGraphics/latest.msgs"))
+        FSCom.remove("/NicheGraphics/latest.msgs");
+    spiLock->unlock();
+
+    if (migrated) {
+        LOG_INFO("InkHUD message migration complete, saving to new format");
+        messageStore.saveToFlash();
+    }
+#endif
+}
+
 // Start InkHUD!
 // Call this only after you have configured InkHUD
 void InkHUD::InkHUD::begin()
 {
     persistence->loadSettings();
+    messageStore.loadFromFlash(); // Load persisted messages before deriving latestMessage cache
+    if (messageStore.getLiveMessages().empty())
+        migrateOldInkHUDMessages(); // First boot after format change: import old per-channel files
     persistence->loadLatestMessage();
 
     windowManager->begin();

src/graphics/niche/InkHUD/MessageStore.cpp

@@ -1,156 +0,0 @@
-#ifdef MESHTASTIC_INCLUDE_INKHUD
-
-#include "./MessageStore.h"
-
-#include "SafeFile.h"
-
-using namespace NicheGraphics;
-
-// Hard limits on how much message data to write to flash
-// Avoid filling the storage if something goes wrong
-// Normal usage should be well below this size
-constexpr uint8_t MAX_MESSAGES_SAVED = 10;
-constexpr uint32_t MAX_MESSAGE_SIZE = 250;
-
-InkHUD::MessageStore::MessageStore(const std::string &label)
-{
-    filename = "";
-    filename += "/NicheGraphics";
-    filename += "/";
-    filename += label;
-    filename += ".msgs";
-}
-
-// Write the contents of the MessageStore::messages object to flash
-// Takes the firmware's SPI lock during FS operations. Implemented for consistency, but only relevant when using SD card.
-// Need to lock and unlock around specific FS methods, as the SafeFile class takes the lock for itself internally
-void InkHUD::MessageStore::saveToFlash()
-{
-    assert(!filename.empty());
-
-#ifdef FSCom
-    // Make the directory, if doesn't already exist
-    // This is the same directory accessed by NicheGraphics::FlashData
-    spiLock->lock();
-    FSCom.mkdir("/NicheGraphics");
-    spiLock->unlock();
-
-    // Open or create the file
-    // No "full atomic": don't save then rename
-    auto f = SafeFile(filename.c_str(), false);
-
-    LOG_INFO("Saving messages in %s", filename.c_str());
-
-    // Take firmware's SPI Lock while writing
-    spiLock->lock();
-
-    // 1st byte: how many messages will be written to store
-    f.write(messages.size());
-
-    // For each message
-    for (uint8_t i = 0; i < messages.size() && i < MAX_MESSAGES_SAVED; i++) {
-        Message &m = messages.at(i);
-        f.write(reinterpret_cast<const uint8_t *>(&m.timestamp), sizeof(m.timestamp));       // Write timestamp. 4 bytes
-        f.write(reinterpret_cast<const uint8_t *>(&m.sender), sizeof(m.sender));             // Write sender NodeId. 4 Bytes
-        f.write(reinterpret_cast<const uint8_t *>(&m.channelIndex), sizeof(m.channelIndex)); // Write channel index. 1 Byte
-        f.write(reinterpret_cast<const uint8_t *>(m.text.c_str()),
-                min((size_t)MAX_MESSAGE_SIZE, m.text.size())); // Write message text
-        f.write('\0');                                         // Append null term
-        LOG_DEBUG("Wrote message %u, length %u, text \"%s\"", static_cast<uint32_t>(i),
-                  min((size_t)MAX_MESSAGE_SIZE, m.text.size()), m.text.c_str());
-    }
-
-    // Release firmware's SPI lock, because SafeFile::close needs it
-    spiLock->unlock();
-
-    bool writeSucceeded = f.close();
-
-    if (!writeSucceeded) {
-        LOG_ERROR("Can't write data!");
-    }
-#else
-    LOG_ERROR("ERROR: Filesystem not implemented\n");
-#endif
-}
-
-// Attempt to load the previous contents of the MessageStore:message deque from flash.
-// Filename is controlled by the "label" parameter
-// Takes the firmware's SPI lock during FS operations. Implemented for consistency, but only relevant when using SD card.
-void InkHUD::MessageStore::loadFromFlash()
-{
-    // Hopefully redundant. Initial intention is to only load / save once per boot.
-    messages.clear();
-
-#ifdef FSCom
-
-    // Take the firmware's SPI Lock, in case filesystem is on SD card
-    concurrency::LockGuard guard(spiLock);
-
-    // Check that the file *does* actually exist
-    if (!FSCom.exists(filename.c_str())) {
-        LOG_WARN("'%s' not found. Using default values", filename.c_str());
-        return;
-    }
-
-    // Check that the file *does* actually exist
-    if (!FSCom.exists(filename.c_str())) {
-        LOG_INFO("'%s' not found.", filename.c_str());
-        return;
-    }
-
-    // Open the file
-    auto f = FSCom.open(filename.c_str(), FILE_O_READ);
-
-    if (f.size() == 0) {
-        LOG_INFO("%s is empty", filename.c_str());
-        f.close();
-        return;
-    }
-
-    // If opened, start reading
-    if (f) {
-        LOG_INFO("Loading threaded messages '%s'", filename.c_str());
-
-        // First byte: how many messages are in the flash store
-        uint8_t flashMessageCount = 0;
-        f.readBytes(reinterpret_cast<char *>(&flashMessageCount), 1);
-        LOG_DEBUG("Messages available: %u", static_cast<uint32_t>(flashMessageCount));
-
-        // For each message
-        for (uint8_t i = 0; i < flashMessageCount && i < MAX_MESSAGES_SAVED; i++) {
-            Message m;
-
-            // Read meta data (fixed width)
-            f.readBytes(reinterpret_cast<char *>(&m.timestamp), sizeof(m.timestamp));
-            f.readBytes(reinterpret_cast<char *>(&m.sender), sizeof(m.sender));
-            f.readBytes(reinterpret_cast<char *>(&m.channelIndex), sizeof(m.channelIndex));
-
-            // Read characters until we find a null term
-            char c;
-            while (m.text.size() < MAX_MESSAGE_SIZE) {
-                f.readBytes(&c, 1);
-                if (c != '\0')
-                    m.text += c;
-                else
-                    break;
-            }
-
-            // Store in RAM
-            messages.push_back(m);
-
-            LOG_DEBUG("#%u, timestamp=%u, sender(num)=%u, text=\"%s\"", static_cast<uint32_t>(i), m.timestamp, m.sender,
-                      m.text.c_str());
-        }
-
-        f.close();
-    } else {
-        LOG_ERROR("Could not open / read %s", filename.c_str());
-    }
-#else
-    LOG_ERROR("Filesystem not implemented");
-    state = LoadFileState::NO_FILESYSTEM;
-#endif
-    return;
-}
-
-#endif

src/graphics/niche/InkHUD/MessageStore.h

@@ -1,47 +0,0 @@
-#ifdef MESHTASTIC_INCLUDE_INKHUD
-
-/*
-
-We hold a few recent messages, for features like the threaded message applet.
-This class contains a struct for storing those messages,
-and methods for serializing them to flash.
-
-*/
-
-#pragma once
-
-#include "configuration.h"
-
-#include <deque>
-
-#include "mesh/MeshTypes.h"
-
-namespace NicheGraphics::InkHUD
-{
-
-class MessageStore
-{
-  public:
-    // A stored message
-    struct Message {
-        uint32_t timestamp; // Epoch seconds
-        NodeNum sender = 0;
-        uint8_t channelIndex;
-        std::string text;
-    };
-
-    MessageStore() = delete;
-    explicit MessageStore(const std::string &label); // Label determines filename in flash
-
-    void saveToFlash();
-    void loadFromFlash();
-
-    std::deque<Message> messages; // Interact with this object!
-
-  private:
-    std::string filename;
-};
-
-} // namespace NicheGraphics::InkHUD
-
-#endif

src/graphics/niche/InkHUD/Persistence.cpp

@@ -17,23 +17,25 @@ void InkHUD::Persistence::loadSettings()
         LOG_WARN("Settings version changed. Using defaults");
 }
 
-// Load settings and latestMessage data
+// Rebuild the latestMessage cache from the global messageStore.
+// Called after messageStore.loadFromFlash() so that the most recent broadcast and DM
+// are immediately available to applets (DMApplet, AllMessageApplet, NotificationApplet).
 void InkHUD::Persistence::loadLatestMessage()
 {
-    // Load previous "latestMessages" data from flash
-    MessageStore store("latest");
-    store.loadFromFlash();
+    latestMessage = LatestMessage();
 
-    // Place into latestMessage struct, for convenient access
-    // Number of strings loaded determines whether last message was broadcast or dm
-    if (store.messages.size() == 1) {
-        latestMessage.dm = store.messages.at(0);
-        latestMessage.wasBroadcast = false;
-    } else if (store.messages.size() == 2) {
-        latestMessage.dm = store.messages.at(0);
-        latestMessage.broadcast = store.messages.at(1);
-        latestMessage.wasBroadcast = true;
+    int lastBroadcastPos = -1, lastDMPos = -1, pos = 0;
+    for (const StoredMessage &m : messageStore.getLiveMessages()) {
+        if (m.type == MessageType::BROADCAST) {
+            latestMessage.broadcast = m;
+            lastBroadcastPos = pos;
+        } else if (m.type == MessageType::DM_TO_US) {
+            latestMessage.dm = m;
+            lastDMPos = pos;
+        }
+        pos++;
     }
+    latestMessage.wasBroadcast = (lastBroadcastPos > lastDMPos);
 }
 
 // Save the InkHUD settings to flash
@@ -42,15 +44,10 @@ void InkHUD::Persistence::saveSettings()
     FlashData<Settings>::save(&settings, "settings");
 }
 
-// Save latestMessage data to flash
+// Persist all messages via the global messageStore.
 void InkHUD::Persistence::saveLatestMessage()
 {
-    // Number of strings saved determines whether last message was broadcast or dm
-    MessageStore store("latest");
-    store.messages.push_back(latestMessage.dm);
-    if (latestMessage.wasBroadcast)
-        store.messages.push_back(latestMessage.broadcast);
-    store.saveToFlash();
+    messageStore.saveToFlash();
 }
 
 /*
@@ -80,4 +77,4 @@ void InkHUD::Persistence::printSettings(Settings *settings)
 }
 */
 
-#endif
+#endif

src/graphics/niche/InkHUD/Persistence.h

@@ -15,7 +15,7 @@ The save / load mechanism is a shared NicheGraphics feature.
 #include "configuration.h"
 
 #include "./InkHUD.h"
-#include "graphics/niche/InkHUD/MessageStore.h"
+#include "MessageStore.h"
 #include "graphics/niche/Utils/FlashData.h"
 
 namespace NicheGraphics::InkHUD
@@ -120,12 +120,12 @@ class Persistence
     };
 
     // Most recently received text message
-    // Value is updated by InkHUD::WindowManager, as a courtesy to applets
-    // InkHUD keeps its own latest-message cache for applets.
+    // Value is updated by InkHUD::Events, as a courtesy to applets.
+    // Populated at boot from the global messageStore, then updated live on receive.
     struct LatestMessage {
-        MessageStore::Message broadcast; // Most recent message received broadcast
-        MessageStore::Message dm;        // Most recent received DM
-        bool wasBroadcast;               // True if most recent broadcast is newer than most recent dm
+        StoredMessage broadcast; // Most recent broadcast message received
+        StoredMessage dm;        // Most recent DM received
+        bool wasBroadcast;       // True if most recent broadcast is newer than most recent dm
     };
 
     void loadSettings();

src/graphics/niche/InkHUD/docs/README.md

@@ -422,9 +422,11 @@ Stores InkHUD data in flash
 - settings
 - most recent text message received (both for broadcast and DM)
 
-In rare cases, applets may store their own specific data separately (e.g. `ThreadedMessageApplet`)
+Message history (used by `ThreadedMessageApplet`) is stored by the firmware-wide `MessageStore` (`src/MessageStore.h`), not by `Persistence` directly.
 
-Data saved only on shutdown / reboot. Not saved if power is removed unexpectedly.
+Settings are saved only on shutdown / reboot. Not saved if power is removed unexpectedly.
+
+Message history is saved periodically (every 2 hours by default), as well as on shutdown / reboot.
 
 ---
 
@@ -466,18 +468,21 @@ Collected here, so various user applets don't all have to store their own copy o
 
 We keep this separate latest-message cache for this purpose, because:
 
-- it is cleared by an outgoing text message
-- we want to store both a recent broadcast and a recent DM
+- we want to expose both the most recent broadcast and most recent DM independently
+- applets like `DMApplet` and `NotificationApplet` need quick access without scanning the full message history
+
+#### How messages reach the store
+
+Broadcasts and DMs take different paths into `messageStore`:
+
+- **Broadcasts** — `ThreadedMessageApplet::handleReceived()` calls `messageStore.addFromPacket()`. `Events::onReceiveTextMessage()` then updates `latestMessage.broadcast` separately for fast access by `AllMessageApplet` and `NotificationApplet`.
+- **DMs** — `ThreadedMessageApplet` skips DMs entirely. `Events::onReceiveTextMessage()` calls `messageStore.addFromPacket()` directly and stores the result in `latestMessage.dm`.
 
 #### Saving / Loading
 
-_A bit of a hack.._
-Stored to flash using `InkHUD::MessageStore`, which is really intended for storing a thread of messages (see `ThreadedMessageApplet`). Used because it stores strings more efficiently than `FlashData.h`.
+The `LatestMessage` cache is not persisted to its own file. On boot, `InkHUD::begin()` calls `messageStore.loadFromFlash()` first, then `Persistence::loadLatestMessage()` rebuilds the cache by scanning the loaded messages for the most recent broadcast and DM.
 
-The hack is:
-
-- If most recent message was a DM, we only store the DM.
-- If most recent message was a broadcast, we store both a DM and a broadcast. The DM may be 0-length string.
+Text is stored in the firmware-wide shared text pool. Use `MessageStore::getText(msg)` to retrieve it from a `StoredMessage`.
 
 ---
 
@@ -582,13 +587,17 @@ Handles events which impact the InkHUD system generally (e.g. shutdown, button p
 
 Applets themselves do also listen separately for various events, but for the purpose of gathering information which they would like to display.
 
+#### Text Messages
+
+`Events::onReceiveTextMessage()` is the central handler for all incoming text messages. It updates the `LatestMessage` cache and, for DMs, also adds the message to `messageStore` (since `ThreadedMessageApplet` only handles broadcasts). See `Persistence::LatestMessage` for details on how the two message types are stored.
+
 #### Buttons
 
 Button input is sometimes handled by a system applet. `InkHUD::Events` determines whether the button should be handled by a specific system applet, or should instead trigger a default behavior
 
 #### Factory Reset
 
-The Events class handles the admin messages(s) which trigger factory reset. We set `Events::eraseOnReboot = true`, which causes `Events::onReboot` to erase the contents of InkHUD's data directory. We do this because some applets (e.g. ThreadedMessageApplet) save their own data to flash, so if we erased earlier, that data would get re-written during reboot.
+The Events class handles the admin message(s) which trigger factory reset. We set `Events::eraseOnReboot = true`, which causes `Events::onReboot` to erase the contents of InkHUD's data directory (`/NicheGraphics/`) and also call `messageStore.clearAllMessages()` to wipe the firmware-wide message store (`/Messages_default.msgs`). Both are cleared during reboot rather than earlier, to avoid data being re-written by applets still running before shutdown.
 
 ---
 

src/input/InputBroker.cpp

@@ -3,6 +3,9 @@
 #include "configuration.h"
 #include "graphics/Screen.h"
 #include "modules/ExternalNotificationModule.h"
+#ifdef MESHTASTIC_LOCKDOWN
+#include "security/LockdownDisplay.h"
+#endif
 
 #if ARCH_PORTDUINO
 #include "input/LinuxInputImpl.h"
@@ -122,6 +125,22 @@ int InputBroker::handleInputEvent(const InputEvent *event)
     }
 #endif
 
+#ifdef MESHTASTIC_LOCKDOWN
+    // Lockdown: when the display is redacted (storage locked, or screen-lock
+    // latch set after idle) the screen content is hidden, but local input
+    // would otherwise still flow into UI handlers — letting an operator
+    // drive menus, fire canned messages, change settings etc. blind. Eat
+    // the event here so input is no-op until the redaction clears.
+    // The latch is cleared only by unlockScreen() on a successful
+    // passphrase auth (see PhoneAPI::handleLockdownAuthInline) — local
+    // input does not clear it, even if storage happens to be unlocked.
+    // PowerFSM was already triggered above, so the backlight still wakes
+    // to show the LOCKED frame — the input just doesn't act on anything.
+    if (meshtastic_security::shouldRedactDisplay()) {
+        return 0;
+    }
+#endif
+
     this->notifyObservers(event);
     return 0;
 }

src/main.cpp

@@ -68,6 +68,19 @@ void nrf54l15Loop();
 NRF54L15Bluetooth *nrf54l15Bluetooth = nullptr;
 #endif
 
+#ifdef MESHTASTIC_ENABLE_APPROTECT
+#include "security/APProtect.h"
+#endif
+#ifdef MESHTASTIC_ENCRYPTED_STORAGE
+#include "security/EncryptedStorage.h"
+#endif
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+#include "mesh/PhoneAPI.h"
+#endif
+#ifdef MESHTASTIC_LOCKDOWN
+#include "security/LockdownDisplay.h"
+#endif
+
 #if HAS_WIFI || defined(USE_WS5500) || defined(USE_CH390D)
 #include "mesh/api/WiFiServerAPI.h"
 #include "mesh/wifi/WiFiAPClient.h"
@@ -379,6 +392,14 @@ void setup()
     consoleInit(); // Set serial baud rate and init our mesh console
 #endif
 
+    // M23 (audit): APPROTECT engagement moved below fsInit() so we can gate
+    // on EncryptedStorage::isProvisioned(). Engaging on an unprovisioned dev
+    // board permanently locks SWD before the operator has even set a
+    // passphrase — a misconfigured CI build flashed to a developer device
+    // would brick its debug port on first boot. Now we only engage when the
+    // device has a DEK file on flash, i.e. the operator has explicitly
+    // committed to lockdown via passphrase provisioning.
+
 #ifdef UNPHONE
     unphone.printStore();
 #endif
@@ -409,7 +430,12 @@ void setup()
 #endif
 #endif
 
-#if defined(DEBUG_MUTE) && defined(DEBUG_PORT)
+    // The DEBUG_MUTE "we are muted, FYI" banner spills APP_VERSION / APP_ENV /
+    // APP_REPO out the USB CDC even with logging otherwise suppressed — a free
+    // firmware-fingerprinting primitive for an attacker holding the cable.
+    // Under MESHTASTIC_LOCKDOWN we want the device to look uniformly silent
+    // until the operator authenticates, so skip the banner entirely there.
+#if defined(DEBUG_MUTE) && defined(DEBUG_PORT) && !defined(MESHTASTIC_LOCKDOWN)
     DEBUG_PORT.printf("\r\n\r\n//\\ E S H T /\\ S T / C\r\n");
     DEBUG_PORT.printf("Version %s for %s from %s\r\n", optstr(APP_VERSION), optstr(APP_ENV), optstr(APP_REPO));
     DEBUG_PORT.printf("Debug mute is enabled, there will be no serial output.\r\n");
@@ -481,6 +507,38 @@ void setup()
 
     fsInit();
 
+#ifdef MESHTASTIC_ENCRYPTED_STORAGE
+    EncryptedStorage::initLocked();
+    if (!EncryptedStorage::isUnlocked()) {
+        if (!EncryptedStorage::isProvisioned()) {
+            LOG_WARN("Lockdown: Device not provisioned — connect and set a passphrase to unlock storage");
+        } else {
+            LOG_WARN("Lockdown: Device locked — connect and provide passphrase to unlock storage");
+        }
+    }
+#endif
+
+#if defined(MESHTASTIC_ENABLE_APPROTECT) && defined(MESHTASTIC_ENCRYPTED_STORAGE)
+    // M23 (audit): only engage the irreversible UICR APPROTECT lockout once
+    // the device has been provisioned with a passphrase. A misconfigured
+    // CI build of a lockdown variant flashed to a developer board would
+    // otherwise burn SWD on first boot before the operator has even set a
+    // passphrase, taking the board out of the dev/recovery workflow with
+    // no real security benefit (there's no DEK to protect yet). Once a
+    // DEK file exists, the operator has committed to lockdown — engaging
+    // APPROTECT then is the protection they asked for.
+    if (EncryptedStorage::isProvisioned()) {
+        enableAPProtect();
+    } else {
+        LOG_INFO("APPROTECT deferred: device not yet provisioned");
+    }
+#elif defined(MESHTASTIC_ENABLE_APPROTECT)
+    // Lockdown without encrypted storage shouldn't be reachable per
+    // configuration.h, but if it ever is, fall back to the unconditional
+    // engagement.
+    enableAPProtect();
+#endif
+
 #if !MESHTASTIC_EXCLUDE_I2C
 #if defined(I2C_SDA1) && defined(ARCH_RP2040)
     Wire1.setSDA(I2C_SDA1);
@@ -998,8 +1056,12 @@ void setup()
 #endif
 #endif
 
-    auto rIf = initLoRa();
-
+    std::unique_ptr<RadioInterface> rIf;
+    if (!config.lora.serial_hal_only) {
+        rIf = initLoRa();
+    } else {
+        LOG_INFO("skipping LoRa radio init, for serialHal");
+    }
     lateInitVariant(); // Do board specific init (see extra_variants/README.md for documentation)
 
 #if !MESHTASTIC_EXCLUDE_MQTT
@@ -1043,10 +1105,9 @@ void setup()
 
     // Start airtime logger thread.
     airTime = new AirTime();
-
-    if (!rIf)
+    if (!rIf && !config.lora.serial_hal_only)
         RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_NO_RADIO);
-    else {
+    else if (rIf) {
         // Log bit rate to debug output
         LOG_DEBUG("LoRA bitrate = %f bytes / sec", (float(meshtastic_Constants_DATA_PAYLOAD_LEN) /
                                                     (float(rIf->getPacketTime(meshtastic_Constants_DATA_PAYLOAD_LEN)))) *
@@ -1077,6 +1138,11 @@ uint32_t rebootAtMsec;     // If not zero we will reboot at this time (used to r
 uint32_t shutdownAtMsec;   // If not zero we will shutdown at this time (used to shutdown from python or mobile client)
 bool suppressRebootBanner; // If true, suppress "Rebooting..." overlay (used for OTA handoff)
 
+#if defined(MESHTASTIC_ENCRYPTED_STORAGE) && defined(MESHTASTIC_PHONEAPI_ACCESS_CONTROL)
+volatile bool lockdownReloadPending;  // see main.h — deferred NodeDB reload after lockdown unlock
+volatile bool lockdownDisablePending; // see main.h — deferred decrypt-revert after lockdown disable
+#endif
+
 // If a thread does something that might need for it to be rescheduled ASAP it can set this flag
 // This will suppress the current delay and instead try to run ASAP.
 bool runASAP;
@@ -1128,7 +1194,7 @@ extern meshtastic_DeviceMetadata getDeviceMetadata()
 // No bluetooth on these targets (yet):
 // Pico W / 2W may get it at some point
 // Portduino and ESP32-C6 are excluded because we don't have a working bluetooth stacks integrated yet.
-#if defined(ARCH_RP2040) || defined(ARCH_PORTDUINO) || defined(ARCH_STM32WL) || defined(CONFIG_IDF_TARGET_ESP32C6)
+#if defined(ARCH_RP2040) || defined(ARCH_PORTDUINO) || defined(ARCH_STM32) || defined(CONFIG_IDF_TARGET_ESP32C6)
     deviceMetadata.excluded_modules |= meshtastic_ExcludedModules_BLUETOOTH_CONFIG;
 #endif
 
@@ -1161,6 +1227,85 @@ void loop()
 {
     runASAP = false;
 
+#if defined(MESHTASTIC_ENCRYPTED_STORAGE) && defined(MESHTASTIC_PHONEAPI_ACCESS_CONTROL)
+    if (lockdownDisablePending) {
+        lockdownDisablePending = false;
+        LOG_INFO("Lockdown: disabling — reverting encrypted storage to plaintext");
+        if (nodeDB->disableLockdownToPlaintext()) {
+            LOG_INFO("Lockdown: disabled, rebooting into normal mode");
+            PhoneAPI::broadcastLockdownStatus(meshtastic_LockdownStatus_State_DISABLED, "", 0, 0, 0);
+            rebootAtMsec = millis() + DEFAULT_REBOOT_SECONDS * 1000;
+        } else {
+            // Revert failed mid-way (a file couldn't be decrypted/rewritten).
+            // The DEK file is still present (it's deleted last), so the device
+            // stays in lockdown and the operator can retry disable. Surface
+            // the failure rather than leaving the client hanging.
+            LOG_ERROR("Lockdown: disable revert failed — device remains in lockdown");
+            PhoneAPI::broadcastLockdownStatus(meshtastic_LockdownStatus_State_LOCKED, "disable_failed", 0, 0, 0);
+        }
+    }
+
+    if (lockdownReloadPending) {
+        lockdownReloadPending = false;
+        LOG_INFO("Lockdown: reloading config from disk after unlock");
+        bool reloadOk = nodeDB->reloadFromDisk();
+        if (!reloadOk) {
+            // Storage decrypt/decode failed during reload. Treat as
+            // unrecoverable for this boot: lock storage, revoke any
+            // auth that managed to slip through (defense in depth — the
+            // cold-unlock path doesn't authorize until completion, but
+            // a concurrent re-verify-path call from another connection
+            // might have), and notify clients. Storage will be locked
+            // on next boot anyway; deferring to the user-visible
+            // notification path is sufficient for now.
+            LOG_ERROR("Lockdown: reload failed — locking and notifying clients");
+            EncryptedStorage::lockNow();
+            PhoneAPI::revokeAllAuth();
+        }
+        PhoneAPI::completePendingUnlocks(reloadOk);
+    }
+
+    // Periodic session-expiry check. Cheap — millis() comparison. Don't
+    // hammer it every loop tick; once a second is plenty.
+    static uint32_t lastSessionCheckMs = 0;
+    if (millis() - lastSessionCheckMs > 1000) {
+        lastSessionCheckMs = millis();
+        if (rebootAtMsec == 0 && EncryptedStorage::isUnlocked() && EncryptedStorage::isSessionExpired()) {
+            // The session expired. Two paths:
+            //   1. Budget remains (bootsRemaining > 0): decrement the
+            //      on-flash boot count in place, revoke per-connection
+            //      auth, re-engage screen redaction, re-arm the uptime
+            //      timer — all WITHOUT rebooting. Storage stays unlocked
+            //      so the mesh keeps routing. Clients must re-authenticate
+            //      to see content again. The decrement is what enforces
+            //      the rollback ceiling — bootsRemaining ticks down
+            //      monotonically whether the device reboots or not.
+            //   2. Budget exhausted (bootsRemaining == 0): no more
+            //      sessions to grant. Hard lock (token deleted, DEK
+            //      zeroed) and reboot. Operator must re-enter passphrase.
+            if (EncryptedStorage::getBootsRemaining() == 0) {
+                LOG_WARN("Lockdown: session limit reached and boot budget exhausted, locking and rebooting");
+                EncryptedStorage::lockNow();
+                PhoneAPI::revokeAllAuth();
+                PhoneAPI::broadcastLockdownStatus(meshtastic_LockdownStatus_State_LOCKED, "session_budget_exhausted", 0, 0, 0);
+                rebootAtMsec = millis() + DEFAULT_REBOOT_SECONDS * 1000;
+            } else {
+                uint8_t newBoots = EncryptedStorage::consumeSessionBoot();
+                LOG_WARN("Lockdown: session expired, rolled to next budget slot (boots=%u remaining)", newBoots);
+                PhoneAPI::revokeAllAuth();
+                meshtastic_security::lockScreen();
+                // Signal clients that they need to re-auth on this
+                // connection. Storage is still unlocked (DEK in RAM,
+                // mesh keeps routing) but per-connection auth is gone.
+                // Reusing the LOCKED(needs_auth) post-config emission
+                // pattern so existing clients don't need a new state.
+                PhoneAPI::broadcastLockdownStatus(meshtastic_LockdownStatus_State_LOCKED, "needs_auth", newBoots,
+                                                  EncryptedStorage::getValidUntilEpoch(), 0);
+            }
+        }
+    }
+#endif
+
 #ifdef ARCH_ESP32
     esp32Loop();
 #endif
@@ -1243,7 +1388,7 @@ void loop()
     }
 #endif
 #endif
-#if HAS_SCREEN && ENABLE_MESSAGE_PERSISTENCE
+#if (HAS_SCREEN || defined(MESHTASTIC_INCLUDE_NICHE_GRAPHICS)) && ENABLE_MESSAGE_PERSISTENCE
     messageStoreAutosaveTick();
 #endif
     long delayMsec = mainController.runOrDelay();

src/main.h

@@ -92,6 +92,19 @@ extern uint32_t rebootAtMsec;
 extern uint32_t shutdownAtMsec;
 extern bool suppressRebootBanner;
 
+#if defined(MESHTASTIC_ENCRYPTED_STORAGE) && defined(MESHTASTIC_PHONEAPI_ACCESS_CONTROL)
+// Set by PhoneAPI::handleLockdownAuthInline after a successful unlock.
+// Serviced on the main loop thread because NodeDB::reloadFromDisk() is
+// too heavy for the BLE/serial transport callback stack.
+extern volatile bool lockdownReloadPending;
+
+// Set by PhoneAPI::handleLockdownAuthInline on a disable request (after the
+// passphrase is verified). Serviced on the main loop thread: decrypt every
+// pref back to plaintext, remove the lockdown artifacts, reboot. Heavy file
+// IO, same reason as lockdownReloadPending.
+extern volatile bool lockdownDisablePending;
+#endif
+
 extern uint32_t serialSinceMsec;
 
 // If a thread does something that might need for it to be rescheduled ASAP it can set this flag

src/memGet.cpp

@@ -14,7 +14,7 @@
 #include <malloc.h>
 #include <unistd.h> // sbrk
 
-#ifdef ARCH_STM32WL
+#if defined(ARCH_STM32)
 // Returns the uncommitted sbrk headroom: addressable space between the current heap
 // break and the stack pointer that has not yet been committed to the arena.
 static uint32_t sbrkHeadroom()

src/mesh/Channels.cpp

@@ -404,6 +404,60 @@ bool Channels::isDefaultChannel(ChannelIndex chIndex)
     return false;
 }
 
+bool cryptoKeyIsPublic(const CryptoKey &key)
+{
+    if (key.length == 0)
+        return true; // encryption disabled
+    // Match the defaultpsk family ignoring its last byte (getKey() bumps only that byte per 1-byte index).
+    if (key.length == (int)sizeof(defaultpsk) && memcmp(key.bytes, defaultpsk, sizeof(defaultpsk) - 1) == 0)
+        return true;
+    return false;
+}
+
+bool Channels::usesPublicKey(ChannelIndex chIndex)
+{
+    const meshtastic_Channel &ch = getByIndex(chIndex);
+    if (!ch.has_settings || ch.role == meshtastic_Channel_Role_DISABLED)
+        return false;
+
+    const auto &psk = ch.settings.psk;
+    if (psk.size == 0) {
+        // Secondary channels inherit the primary key when unset; primary size==0 means encryption disabled.
+        if (ch.role == meshtastic_Channel_Role_SECONDARY) {
+            // Guard against malformed configs with no PRIMARY channel (primaryIndex could point back to us).
+            if (primaryIndex == chIndex)
+                return true; // fail closed: treat as public
+            return usesPublicKey(primaryIndex);
+        }
+        return true;
+    }
+
+    if (psk.size == 1) {
+        // Short PSK aliases: 0 disables encryption; 1..255 are the public defaultpsk family.
+        return true;
+    }
+
+    return (psk.size == sizeof(defaultpsk) && memcmp(psk.bytes, defaultpsk, sizeof(defaultpsk) - 1) == 0);
+}
+
+bool Channels::isWellKnownChannel(ChannelIndex chIndex)
+{
+    const auto &ch = getByIndex(chIndex);
+    // Absent (unencrypted) or single-byte PSK — all the well-known key indexes
+    if (ch.settings.psk.size > 1)
+        return false;
+
+    const char *name = getName(chIndex);
+    for (int p = _meshtastic_Config_LoRaConfig_ModemPreset_MIN; p <= _meshtastic_Config_LoRaConfig_ModemPreset_MAX; p++) {
+        const char *presetName =
+            DisplayFormatters::getModemPresetDisplayName(static_cast<meshtastic_Config_LoRaConfig_ModemPreset>(p), false, true);
+        // Presets without a display name fall through to "Invalid" — never a match
+        if (strcmp(presetName, "Invalid") != 0 && strcmp(name, presetName) == 0)
+            return true;
+    }
+    return false;
+}
+
 bool Channels::hasDefaultChannel()
 {
     // If we don't use a preset or the default frequency slot, or we override the frequency, we don't have a default channel

src/mesh/Channels.h

@@ -86,6 +86,15 @@ class Channels
     // Returns true if the channel has the default name and PSK
     bool isDefaultChannel(ChannelIndex chIndex);
 
+    // Returns true if this channel's effective key is publicly decryptable (open or well-known/default PSK).
+    bool usesPublicKey(ChannelIndex chIndex);
+    // Returns true if the channel is "well known": its PSK is absent or a
+    // single-byte well-known key index, AND its name is any modem-preset
+    // display name (e.g. a channel named "LongFast" counts even while the
+    // radio runs MediumFast). Broader than isDefaultChannel, which only
+    // matches the current preset's name and PSK byte 1.
+    bool isWellKnownChannel(ChannelIndex chIndex);
+
     // Returns true if we can be reached via a channel with the default settings given a region and modem preset
     bool hasDefaultChannel();
 
@@ -144,6 +153,9 @@ extern Channels channels;
 static const uint8_t defaultpsk[] = {0xd4, 0xf1, 0xbb, 0x3a, 0x20, 0x29, 0x07, 0x59,
                                      0xf0, 0xbc, 0xff, 0xab, 0xcf, 0x4e, 0x69, 0x01};
 
+/// True if a getKey()-resolved key offers no privacy: length 0 (off) or the public defaultpsk family. Pure; for tests.
+bool cryptoKeyIsPublic(const CryptoKey &key);
+
 static const uint8_t eventpsk[] = {0x38, 0x4b, 0xbc, 0xc0, 0x1d, 0xc0, 0x22, 0xd1, 0x81, 0xbf, 0x36,
                                    0xb8, 0x61, 0x21, 0xe1, 0xfb, 0x96, 0xb7, 0x2e, 0x55, 0xbf, 0x74,
                                    0x22, 0x7e, 0x9d, 0x6a, 0xfb, 0x48, 0xd6, 0x4c, 0xb1, 0xa1};

src/mesh/CryptoEngine.cpp

@@ -12,10 +12,18 @@
 #include <Curve25519.h>
 #include <RNG.h>
 #include <SHA256.h>
-#if !(MESHTASTIC_EXCLUDE_PKI_KEYGEN)
-#if !defined(ARCH_STM32WL)
-#define CryptRNG RNG
+
+#if !(MESHTASTIC_EXCLUDE_XEDDSA)
+#include "XEdDSA.h"
+#include <Ed25519.h>
+
+#ifndef NUM_LIMBS_256BIT
+#define NUM_LIMBS_BITS(n) (((n) + sizeof(limb_t) * 8 - 1) / (8 * sizeof(limb_t)))
+#define NUM_LIMBS_256BIT NUM_LIMBS_BITS(256)
 #endif
+#endif
+
+#if !(MESHTASTIC_EXCLUDE_PKI_KEYGEN)
 
 /**
  * Create a public/private key pair with Curve25519.
@@ -46,6 +54,9 @@ void CryptoEngine::generateKeyPair(uint8_t *pubKey, uint8_t *privKey)
     Curve25519::dh1(public_key, private_key);
     memcpy(pubKey, public_key, sizeof(public_key));
     memcpy(privKey, private_key, sizeof(private_key));
+#if !(MESHTASTIC_EXCLUDE_XEDDSA)
+    XEdDSA::priv_curve_to_ed_keys(private_key, xeddsa_private_key, xeddsa_public_key);
+#endif
 }
 
 /**
@@ -65,6 +76,9 @@ bool CryptoEngine::regeneratePublicKey(uint8_t *pubKey, uint8_t *privKey)
         }
         memcpy(private_key, privKey, sizeof(private_key));
         memcpy(public_key, pubKey, sizeof(public_key));
+#if !(MESHTASTIC_EXCLUDE_XEDDSA)
+        XEdDSA::priv_curve_to_ed_keys(private_key, xeddsa_private_key, xeddsa_public_key);
+#endif
     } else {
         LOG_WARN("X25519 key generation failed due to blank private key");
         return false;
@@ -72,6 +86,97 @@ bool CryptoEngine::regeneratePublicKey(uint8_t *pubKey, uint8_t *privKey)
     return true;
 }
 
+#if !(MESHTASTIC_EXCLUDE_XEDDSA)
+/**
+ * Build a signing buffer that covers packet metadata and payload:
+ *   [fromNode(4) | packetId(4) | portnum(4) | payload(N)]
+ * This prevents replay, reattribution, and portnum redirection attacks.
+ */
+static size_t buildSigningBuffer(uint8_t *buf, size_t bufSize, uint32_t fromNode, uint32_t packetId, uint32_t portnum,
+                                 const uint8_t *payload, size_t payloadLen)
+{
+    const size_t headerLen = sizeof(uint32_t) * 3;
+    size_t totalLen = headerLen + payloadLen;
+    if (totalLen > bufSize)
+        return 0;
+    // May need endian conversion for oddball platforms.
+    memcpy(buf, &fromNode, sizeof(uint32_t));
+    memcpy(buf + sizeof(uint32_t), &packetId, sizeof(uint32_t));
+    memcpy(buf + sizeof(uint32_t) * 2, &portnum, sizeof(uint32_t));
+    memcpy(buf + headerLen, payload, payloadLen);
+    return totalLen;
+}
+
+bool CryptoEngine::xeddsa_sign(uint32_t fromNode, uint32_t packetId, uint32_t portnum, const uint8_t *payload, size_t payloadLen,
+                               uint8_t *signature)
+{
+    if (memfll(xeddsa_private_key, 0, sizeof(xeddsa_private_key)))
+        return false;
+    uint8_t sigBuf[MAX_BLOCKSIZE];
+    size_t sigLen = buildSigningBuffer(sigBuf, sizeof(sigBuf), fromNode, packetId, portnum, payload, payloadLen);
+    if (sigLen == 0)
+        return false;
+    // the XEdDSA::sign function requires at least the first 32 bytes of signature to be pre-filled with randomness
+    HardwareRNG::fill(signature, 32);
+    XEdDSA::sign(signature, xeddsa_private_key, xeddsa_public_key, sigBuf, sigLen);
+    return true;
+}
+
+bool CryptoEngine::xeddsa_verify(const uint8_t *pubKey, uint32_t fromNode, uint32_t packetId, uint32_t portnum,
+                                 const uint8_t *payload, size_t payloadLen, const uint8_t *signature)
+{
+    // Use cached Ed25519 key if the Curve25519 key matches, avoiding expensive field inversion
+    if (memcmp(pubKey, cached_curve_pubkey, 32) != 0) {
+        curve_to_ed_pub(pubKey, cached_ed_pubkey);
+        memcpy(cached_curve_pubkey, pubKey, 32);
+    }
+    uint8_t sigBuf[MAX_BLOCKSIZE];
+    size_t sigLen = buildSigningBuffer(sigBuf, sizeof(sigBuf), fromNode, packetId, portnum, payload, payloadLen);
+    if (sigLen == 0)
+        return false;
+    return XEdDSA::verify(signature, cached_ed_pubkey, sigBuf, sigLen);
+}
+
+void CryptoEngine::curve_to_ed_pub(const uint8_t *curve_pubkey, uint8_t *ed_pubkey)
+{
+
+    // Apply the birational map defined in RFC 7748, section 4.1 "Curve25519" to calculate an Ed25519 public
+    // key from a Curve25519 public key. Because the serialization format of Curve25519 public keys only
+    // contains the u coordinate, the x coordinate of the corresponding Ed25519 public key can't be uniquely
+    // calculated as defined by the birational map. The x coordinate is represented in the serialization
+    // format of Ed25519 public keys only in a single sign bit. XEdDSA always normalizes the Ed25519 public
+    // key to a sign bit of zero (the signer negates its key pair when needed), so this function clears the
+    // sign bit unconditionally below instead of taking it as an input.
+    fe u, y;
+    fe one;
+    fe u_minus_one, u_plus_one, u_plus_one_inv;
+
+    // Parse the Curve25519 public key input as a field element containing the u coordinate. RFC 7748,
+    // section 5 "The X25519 and X448 Functions", mandates that the most significant bit of the Curve25519
+    // public key has to be zeroized. This is handled by fe_frombytes internally.
+    fe_frombytes(u, curve_pubkey);
+
+    // Calculate the parameters (u - 1) and (u + 1)
+    fe_1(one);
+    fe_sub(u_minus_one, u, one);
+    fe_add(u_plus_one, u, one);
+
+    // Invert u + 1
+    fe_invert(u_plus_one_inv, u_plus_one);
+
+    // Calculate y = (u - 1) * inv(u + 1) (mod p)
+    fe_mul(y, u_minus_one, u_plus_one_inv);
+
+    // Serialize the field element containing the y coordinate to the Ed25519 public key output
+    fe_tobytes(ed_pubkey, y);
+
+    // Set the sign bit to zero
+    ed_pubkey[31] &= 0x7f;
+
+    // need to convert the pubkey y = ( u - 1) * inv( u + 1) (mod p).
+}
+#endif
+
 bool CryptoEngine::ensurePkiKeys(meshtastic_Config_SecurityConfig &security, meshtastic_User &user)
 {
     if (user.is_licensed) {

src/mesh/CryptoEngine.h

@@ -23,6 +23,7 @@ struct CryptoKey {
 
 #define MAX_BLOCKSIZE 256
 #define TEST_CURVE25519_FIELD_OPS // Exposes Curve25519::isWeakPoint() for testing keys
+#define XEDDSA_SIGNATURE_SIZE 64
 
 class CryptoEngine
 {
@@ -37,7 +38,12 @@ class CryptoEngine
     virtual void generateKeyPair(uint8_t *pubKey, uint8_t *privKey);
     virtual bool regeneratePublicKey(uint8_t *pubKey, uint8_t *privKey);
     virtual bool ensurePkiKeys(meshtastic_Config_SecurityConfig &security, meshtastic_User &user);
-
+#endif
+#if !(MESHTASTIC_EXCLUDE_XEDDSA)
+    bool xeddsa_sign(uint32_t fromNode, uint32_t packetId, uint32_t portnum, const uint8_t *payload, size_t payloadLen,
+                     uint8_t *signature);
+    bool xeddsa_verify(const uint8_t *pubKey, uint32_t fromNode, uint32_t packetId, uint32_t portnum, const uint8_t *payload,
+                       size_t payloadLen, const uint8_t *signature);
 #endif
     void setDHPrivateKey(uint8_t *_private_key);
     // The remotePublic key parameter takes the public_key bytes container from
@@ -85,6 +91,14 @@ class CryptoEngine
 #if !(MESHTASTIC_EXCLUDE_PKI)
     uint8_t shared_key[32] = {0};
     uint8_t private_key[32] = {0};
+#if !(MESHTASTIC_EXCLUDE_XEDDSA)
+    uint8_t xeddsa_public_key[32] = {0};
+    uint8_t xeddsa_private_key[32] = {0};
+    void curve_to_ed_pub(const uint8_t *curve_pubkey, uint8_t *ed_pubkey);
+    // Single-entry cache for curve_to_ed_pub conversion (avoids expensive field inversion per packet)
+    uint8_t cached_curve_pubkey[32] = {0};
+    uint8_t cached_ed_pubkey[32] = {0};
+#endif
 #endif
     /**
      * Init our 128 bit nonce for a new packet

src/mesh/Default.h

@@ -18,6 +18,9 @@
 #define default_telemetry_broadcast_interval_secs IF_ROUTER(ONE_DAY / 2, 60 * 60)
 #define default_broadcast_interval_secs IF_ROUTER(ONE_DAY / 2, 60 * 60)
 #define default_broadcast_smart_minimum_interval_secs 5 * 60
+// Floor for our own position broadcasts when stationary (unchanged beyond the broadcast
+// precision) or fixed_position: identical positions get deduped by traffic management anyway.
+#define default_position_stationary_broadcast_secs (12 * 60 * 60)
 #define min_default_broadcast_interval_secs IF_ROUTER(ONE_DAY / 2, 60 * 60)
 #define min_default_broadcast_smart_minimum_interval_secs 5 * 60
 #define default_wait_bluetooth_secs IF_ROUTER(1, 60)
@@ -34,8 +37,14 @@
 enum class TrafficType { POSITION, TELEMETRY };
 
 // Traffic management defaults
-#define default_traffic_mgmt_position_precision_bits 24               // ~10m grid cells
-#define default_traffic_mgmt_position_min_interval_secs (ONE_DAY / 2) // 12 hours between identical positions
+#define default_traffic_mgmt_position_precision_bits 19                // ~90m grid cells (±45m)
+#define default_traffic_mgmt_position_min_interval_secs (11 * 60 * 60) // 11 hours between identical positions
+// Role cap: tracker-role origins may refresh a duplicate position this often (vs the 11h default).
+#define default_traffic_mgmt_tracker_position_min_interval_secs (60 * 60) // 1 hour
+// Role cap: lost-and-found origins may refresh a duplicate position this often, so a lost
+// device updates frequently without flooding. (Quantised to the dedup tick: ~2 ticks.)
+// Unlike before, lost-and-found is NOT exempt from the relayed precision clamp.
+#define default_traffic_mgmt_lost_and_found_position_min_interval_secs (15 * 60) // 15 minutes
 
 // Hop scaling defaults
 #define default_hop_scaling_min_target_nodes 40          // walk threshold: first hop reaching this cumulative count

src/mesh/LoRaFEMInterface.cpp

@@ -2,14 +2,66 @@
 #include "LoRaFEMInterface.h"
 
 #if defined(ARCH_ESP32)
+#include <driver/gpio.h>
 #include <driver/rtc_io.h>
 #include <esp_sleep.h>
 #endif
 
 LoRaFEMInterface loraFEMInterface;
+
+static void enableFEMPower()
+{
+    bool wasOff = digitalRead(LORA_PA_POWER) != HIGH;
+    digitalWrite(LORA_PA_POWER, HIGH);
+    if (wasOff) {
+        delay(5); // This is an arbitrary 5ms for FEM rail power-up.
+    }
+}
+
+#if defined(ARCH_ESP32)
+static void releasePinHold(int pin)
+{
+    if (pin < 0) {
+        return;
+    }
+
+    gpio_num_t gpio = (gpio_num_t)pin;
+
+#if SOC_RTCIO_HOLD_SUPPORTED
+    if (rtc_gpio_is_valid_gpio(gpio)) {
+        rtc_gpio_hold_dis(gpio);
+        return;
+    }
+#endif
+    if (GPIO_IS_VALID_OUTPUT_GPIO(gpio)) {
+        gpio_hold_dis(gpio);
+    }
+}
+
+static void releaseSleepHolds()
+{
+    releasePinHold(LORA_PA_POWER);
+#ifdef HELTEC_V4
+    releasePinHold(LORA_KCT8103L_PA_CSD);
+    releasePinHold(LORA_KCT8103L_PA_CTX);
+#elif defined(USE_GC1109_PA)
+    releasePinHold(LORA_GC1109_PA_EN);
+    releasePinHold(LORA_GC1109_PA_TX_EN);
+#elif defined(USE_KCT8103L_PA)
+    releasePinHold(LORA_KCT8103L_PA_CSD);
+    releasePinHold(LORA_KCT8103L_PA_CTX);
+#endif
+}
+#endif
+
 void LoRaFEMInterface::init(void)
 {
     setLnaCanControl(false); // Default is uncontrollable
+#if defined(RF_PA_DETECT_PIN)
+    pinMode(RF_PA_DETECT_PIN, INPUT);
+    high_power_pa = (digitalRead(RF_PA_DETECT_PIN) == RF_PA_HIGH_POWER_VALUE);
+    LOG_INFO("Detected %s LoRa PA profile", high_power_pa ? "high-power" : "low-power");
+#endif
 #ifdef HELTEC_V4
     pinMode(LORA_PA_POWER, OUTPUT);
     digitalWrite(LORA_PA_POWER, HIGH);
@@ -21,6 +73,7 @@ void LoRaFEMInterface::init(void)
     if (digitalRead(LORA_KCT8103L_PA_CSD) == HIGH) {
         // FEM is KCT8103L
         fem_type = KCT8103L_PA;
+        LOG_INFO("Detected KCT8103L LoRa FEM");
         rtc_gpio_hold_dis((gpio_num_t)LORA_KCT8103L_PA_CTX);
         pinMode(LORA_KCT8103L_PA_CSD, OUTPUT);
         digitalWrite(LORA_KCT8103L_PA_CSD, HIGH);
@@ -30,6 +83,7 @@ void LoRaFEMInterface::init(void)
     } else if (digitalRead(LORA_KCT8103L_PA_CSD) == LOW) {
         // FEM is GC1109
         fem_type = GC1109_PA;
+        LOG_INFO("Detected GC1109 LoRa FEM");
         // LORA_GC1109_PA_EN and LORA_KCT8103L_PA_CSD are the same pin and do not need to be repeatedly turned off and held.
         //  rtc_gpio_hold_dis((gpio_num_t)LORA_GC1109_PA_EN);
         pinMode(LORA_GC1109_PA_EN, OUTPUT);
@@ -41,6 +95,7 @@ void LoRaFEMInterface::init(void)
     }
 #elif defined(USE_GC1109_PA)
     fem_type = GC1109_PA;
+    LOG_INFO("Using GC1109 LoRa FEM");
     pinMode(LORA_PA_POWER, OUTPUT);
     digitalWrite(LORA_PA_POWER, HIGH);
 #if defined(ARCH_ESP32)
@@ -55,6 +110,7 @@ void LoRaFEMInterface::init(void)
     digitalWrite(LORA_GC1109_PA_TX_EN, LOW);
 #elif defined(USE_KCT8103L_PA)
     fem_type = KCT8103L_PA;
+    LOG_INFO("Using KCT8103L LoRa FEM");
     pinMode(LORA_PA_POWER, OUTPUT);
     digitalWrite(LORA_PA_POWER, HIGH);
 #if defined(ARCH_ESP32)
@@ -68,11 +124,22 @@ void LoRaFEMInterface::init(void)
     pinMode(LORA_KCT8103L_PA_CTX, OUTPUT);
     digitalWrite(LORA_KCT8103L_PA_CTX, LOW); // LNA enabled by default
     setLnaCanControl(true);
+#elif defined(USE_KCT8103L_PA_ONLY)
+    fem_type = KCT8103L_PA;
+    pinMode(LORA_KCT8103L_EN, OUTPUT);
+    digitalWrite(LORA_KCT8103L_EN, HIGH);
+    delay(1);
+    pinMode(LORA_KCT8103L_TX_RX, OUTPUT);
+    digitalWrite(LORA_KCT8103L_TX_RX, LOW);
 #endif
 }
 
 void LoRaFEMInterface::setSleepModeEnable(void)
 {
+#if defined(ARCH_ESP32)
+    releaseSleepHolds();
+#endif
+
 #ifdef HELTEC_V4
     if (fem_type == GC1109_PA) {
         /*
@@ -84,6 +151,7 @@ void LoRaFEMInterface::setSleepModeEnable(void)
     } else if (fem_type == KCT8103L_PA) {
         // shutdown the PA
         digitalWrite(LORA_KCT8103L_PA_CSD, LOW);
+        digitalWrite(LORA_PA_POWER, LOW);
     }
 #elif defined(USE_GC1109_PA)
     digitalWrite(LORA_GC1109_PA_EN, LOW);
@@ -91,16 +159,25 @@ void LoRaFEMInterface::setSleepModeEnable(void)
 #elif defined(USE_KCT8103L_PA)
     // shutdown the PA
     digitalWrite(LORA_KCT8103L_PA_CSD, LOW);
+    digitalWrite(LORA_PA_POWER, LOW);
+#elif defined(USE_KCT8103L_PA_ONLY)
+    // shutdown the PA
+    digitalWrite(LORA_KCT8103L_EN, LOW);
 #endif
 }
 
 void LoRaFEMInterface::setTxModeEnable(void)
 {
+#if defined(ARCH_ESP32)
+    releaseSleepHolds();
+#endif
+
 #ifdef HELTEC_V4
     if (fem_type == GC1109_PA) {
         digitalWrite(LORA_GC1109_PA_EN, HIGH);    // CSD=1: Chip enabled
         digitalWrite(LORA_GC1109_PA_TX_EN, HIGH); // CPS: 1=full PA, 0=bypass (for RX, CPS is don't care)
     } else if (fem_type == KCT8103L_PA) {
+        enableFEMPower();
         digitalWrite(LORA_KCT8103L_PA_CSD, HIGH);
         digitalWrite(LORA_KCT8103L_PA_CTX, HIGH);
     }
@@ -108,18 +185,27 @@ void LoRaFEMInterface::setTxModeEnable(void)
     digitalWrite(LORA_GC1109_PA_EN, HIGH);    // CSD=1: Chip enabled
     digitalWrite(LORA_GC1109_PA_TX_EN, HIGH); // CPS: 1=full PA, 0=bypass (for RX, CPS is don't care)
 #elif defined(USE_KCT8103L_PA)
+    enableFEMPower();
     digitalWrite(LORA_KCT8103L_PA_CSD, HIGH);
     digitalWrite(LORA_KCT8103L_PA_CTX, HIGH);
+#elif defined(USE_KCT8103L_PA_ONLY)
+    enableFEMPower();
+    digitalWrite(LORA_KCT8103L_TX_RX, HIGH);
 #endif
 }
 
 void LoRaFEMInterface::setRxModeEnable(void)
 {
+#if defined(ARCH_ESP32)
+    releaseSleepHolds();
+#endif
+
 #ifdef HELTEC_V4
     if (fem_type == GC1109_PA) {
         digitalWrite(LORA_GC1109_PA_EN, HIGH); // CSD=1: Chip enabled
         digitalWrite(LORA_GC1109_PA_TX_EN, LOW);
     } else if (fem_type == KCT8103L_PA) {
+        enableFEMPower();
         digitalWrite(LORA_KCT8103L_PA_CSD, HIGH);
         if (lna_enabled) {
             digitalWrite(LORA_KCT8103L_PA_CTX, LOW);
@@ -131,23 +217,29 @@ void LoRaFEMInterface::setRxModeEnable(void)
     digitalWrite(LORA_GC1109_PA_EN, HIGH);    // CSD=1: Chip enabled
     digitalWrite(LORA_GC1109_PA_TX_EN, LOW);
 #elif defined(USE_KCT8103L_PA)
+    enableFEMPower();
     digitalWrite(LORA_KCT8103L_PA_CSD, HIGH);
     if (lna_enabled) {
         digitalWrite(LORA_KCT8103L_PA_CTX, LOW);
     } else {
         digitalWrite(LORA_KCT8103L_PA_CTX, HIGH);
     }
+#elif defined(USE_KCT8103L_PA_ONLY)
+    enableFEMPower();
+    digitalWrite(LORA_KCT8103L_TX_RX, LOW);
 #endif
 }
 
 void LoRaFEMInterface::setRxModeEnableWhenMCUSleep(void)
 {
+#if defined(ARCH_ESP32)
+    releaseSleepHolds();
+#endif
 
 #ifdef HELTEC_V4
-    // Keep GC1109 FEM powered during deep sleep so LNA remains active for RX wake.
-    // Set PA_POWER and PA_EN HIGH (overrides SX126xInterface::sleep() shutdown),
-    // then latch with RTC hold so the state survives deep sleep.
-    digitalWrite(LORA_PA_POWER, HIGH);
+    // Keep FEM rail powered during deep sleep so LoRa RX wake can work (GC1109 keeps LNA active; KCT8103L uses RX bypass).
+    // Set PA_POWER HIGH (overrides SX126xInterface::sleep() shutdown), then latch with RTC hold so the state survives deep sleep.
+    enableFEMPower();
     rtc_gpio_hold_en((gpio_num_t)LORA_PA_POWER);
     if (fem_type == GC1109_PA) {
         digitalWrite(LORA_GC1109_PA_EN, HIGH);
@@ -156,15 +248,11 @@ void LoRaFEMInterface::setRxModeEnableWhenMCUSleep(void)
     } else if (fem_type == KCT8103L_PA) {
         digitalWrite(LORA_KCT8103L_PA_CSD, HIGH);
         rtc_gpio_hold_en((gpio_num_t)LORA_KCT8103L_PA_CSD);
-        if (lna_enabled) {
-            digitalWrite(LORA_KCT8103L_PA_CTX, LOW);
-        } else {
-            digitalWrite(LORA_KCT8103L_PA_CTX, HIGH);
-        }
+        digitalWrite(LORA_KCT8103L_PA_CTX, HIGH); // RX bypass while MCU sleeps
         rtc_gpio_hold_en((gpio_num_t)LORA_KCT8103L_PA_CTX);
     }
 #elif defined(USE_GC1109_PA)
-    digitalWrite(LORA_PA_POWER, HIGH);
+    enableFEMPower();
     digitalWrite(LORA_GC1109_PA_EN, HIGH);
 #if defined(ARCH_ESP32)
     rtc_gpio_hold_en((gpio_num_t)LORA_PA_POWER);
@@ -172,16 +260,17 @@ void LoRaFEMInterface::setRxModeEnableWhenMCUSleep(void)
     gpio_pulldown_en((gpio_num_t)LORA_GC1109_PA_TX_EN);
 #endif
 #elif defined(USE_KCT8103L_PA)
+    enableFEMPower();
     digitalWrite(LORA_KCT8103L_PA_CSD, HIGH);
-    if (lna_enabled) {
-        digitalWrite(LORA_KCT8103L_PA_CTX, LOW);
-    } else {
-        digitalWrite(LORA_KCT8103L_PA_CTX, HIGH);
-    }
+    digitalWrite(LORA_KCT8103L_PA_CTX, HIGH); // RX bypass while MCU sleeps
 #if defined(ARCH_ESP32)
+    rtc_gpio_hold_en((gpio_num_t)LORA_PA_POWER);
     rtc_gpio_hold_en((gpio_num_t)LORA_KCT8103L_PA_CSD);
     rtc_gpio_hold_en((gpio_num_t)LORA_KCT8103L_PA_CTX);
 #endif
+#elif defined(USE_KCT8103L_PA_ONLY)
+    enableFEMPower();
+    digitalWrite(LORA_KCT8103L_TX_RX, LOW);
 #endif
 }
 
@@ -192,6 +281,11 @@ void LoRaFEMInterface::setLNAEnable(bool enabled)
 
 int8_t LoRaFEMInterface::powerConversion(int8_t loraOutputPower)
 {
+#if defined(RF_PA_DETECT_PIN)
+    if (!high_power_pa) {
+        return loraOutputPower;
+    }
+#endif
 #ifdef HELTEC_V4
     const uint16_t gc1109_tx_gain[] = {11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 10, 10, 9, 9, 8, 7};
     const uint16_t kct8103l_tx_gain[] = {13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 12, 12, 11, 11, 10, 9, 8, 7};
@@ -227,4 +321,4 @@ int8_t LoRaFEMInterface::powerConversion(int8_t loraOutputPower)
     return loraOutputPower;
 }
 
-#endif
+#endif

src/mesh/LoRaFEMInterface.h

@@ -24,7 +24,8 @@ class LoRaFEMInterface
     LoRaFEMType fem_type;
     bool lna_enabled = true;
     bool lna_can_control = false;
+    bool high_power_pa = true;
 };
 extern LoRaFEMInterface loraFEMInterface;
 
-#endif
+#endif

src/mesh/MeshRadio.h

@@ -45,6 +45,7 @@ extern const RegionProfile PROFILE_UNDEF;
 extern const RegionProfile PROFILE_LITE;
 extern const RegionProfile PROFILE_NARROW;
 extern const RegionProfile PROFILE_HAM_20KHZ;
+extern const RegionProfile PROFILE_HAM_100KHZ;
 
 // Map from old region names to new region enums
 struct RegionInfo {
@@ -64,6 +65,14 @@ struct RegionInfo {
     // Preset accessors (delegate through profile)
     meshtastic_Config_LoRaConfig_ModemPreset getDefaultPreset() const { return defaultPreset; }
     const meshtastic_Config_LoRaConfig_ModemPreset *getAvailablePresets() const { return profile->presets; }
+    bool supportsPreset(meshtastic_Config_LoRaConfig_ModemPreset preset) const
+    {
+        for (size_t i = 0; profile->presets[i] != MODEM_PRESET_END; i++) {
+            if (profile->presets[i] == preset)
+                return true;
+        }
+        return false;
+    }
     size_t getNumPresets() const
     {
         size_t n = 0;
@@ -79,6 +88,11 @@ extern const RegionInfo *myRegion;
 extern void initRegion();
 extern const RegionInfo *getRegion(meshtastic_Config_LoRaConfig_RegionCode code);
 
+// Fill `map` with the region->valid-preset table, grouped so regions sharing a
+// preset list reference the same group. Sent to clients during want_config so
+// their UI can block illegal region+preset combinations.
+extern void getRegionPresetMap(meshtastic_LoRaRegionPresetMap &map);
+
 // Valid LoRa spread factor range and defaults
 constexpr uint8_t LORA_SF_MIN = 5;
 constexpr uint8_t LORA_SF_MAX = 12;

src/mesh/MeshService.h

@@ -141,6 +141,12 @@ class MeshService
     /// Release the next ClientNotification packet to pool.
     void releaseClientNotificationToPool(meshtastic_ClientNotification *p) { clientNotificationPool.release(p); }
 
+    /// Bump fromNum to signal connected clients to poll for new FromRadio data.
+    /// Used by code paths (e.g. lockdown status queueing) that surface a new
+    /// FromRadio variant without going through one of the existing pool-backed
+    /// senders.
+    void nudgeFromNum() { fromNum++; }
+
     /**
      *  Given a ToRadio buffer parse it and properly handle it (setup radio, owner or send packet into the mesh)
      * Called by PhoneAPI.handleToRadio.  Note: p is a scratch buffer, this function is allowed to write to it but it can not keep

src/mesh/MeshTypes.h

@@ -45,6 +45,11 @@ enum RxSource {
 // For old firmware there is no relay node set
 #define NO_RELAY_NODE 0
 
+// How recently we must have heard a direct neighbor for its single-byte relay id to be trusted as a
+// unique next hop. Mirrors NUM_ONLINE_SECS (NodeDB.cpp). Used by NodeDB::resolveLastByte() to scope
+// last-byte collision resolution to currently-reachable neighbors.
+#define NEXTHOP_NEIGHBOR_FRESH_SECS (60 * 60 * 2) // 2 hrs
+
 typedef int ErrorCode;
 
 /// Alloc and free packets to our global, ISR safe pool

src/mesh/NextHopRouter.cpp

@@ -98,21 +98,38 @@ void NextHopRouter::sniffReceived(const meshtastic_MeshPacket *p, const meshtast
         // destination
         if (p->from != 0) {
             meshtastic_NodeInfoLite *origTx = nodeDB->getMeshNode(p->from);
-            if (origTx) {
-                // Either relayer of ACK was also a relayer of the packet, or we were the *only* relayer and the ACK came
-                // directly from the destination
-                // Single lookup for both relayer checks on the same (request_id, to) pair
-                bool wasAlreadyRelayer = false;
-                bool weWereSoleRelayer = false;
-                bool weWereRelayer = false;
-                checkRelayers(p->relay_node, ourRelayID, p->decoded.request_id, p->to, &wasAlreadyRelayer, &weWereRelayer,
-                              &weWereSoleRelayer);
-                if ((weWereRelayer && wasAlreadyRelayer) || (getHopsAway(*p) == 0 && weWereSoleRelayer)) {
-                    if (origTx->next_hop != p->relay_node) { // Not already set
+            // Either relayer of ACK was also a relayer of the packet, or we were the *only* relayer and the ACK came
+            // directly from the destination. checkRelayers is read-only on PacketHistory and O(1), so we run it even
+            // when origTx is absent — that lets us still capture the confirmed hop into the TMM overflow cache below.
+            // Single lookup for both relayer checks on the same (request_id, to) pair
+            bool wasAlreadyRelayer = false;
+            bool weWereSoleRelayer = false;
+            bool weWereRelayer = false;
+            checkRelayers(p->relay_node, ourRelayID, p->decoded.request_id, p->to, &wasAlreadyRelayer, &weWereRelayer,
+                          &weWereSoleRelayer);
+            if ((weWereRelayer && wasAlreadyRelayer) || (getHopsAway(*p) == 0 && weWereSoleRelayer)) {
+                // M1/M2: only learn a next hop whose last byte maps to a single plausible relay. On a dense
+                // mesh the byte may be ambiguous; storing it would aim future DMs at the wrong node. This gate
+                // now protects BOTH the hot-store route (NodeInfoLite.next_hop) AND the TMM overflow cache —
+                // the overflow cache deliberately holds many more next-hop bytes (long-tail nodes), so it is
+                // even more collision-prone and must never store an ambiguous byte either. Ambiguous/unknown
+                // -> store nothing and keep flooding (safe).
+                if (nodeDB->resolveUniqueLastByte(p->relay_node, /*requireDirectNeighbor=*/false)) {
+                    if (origTx && origTx->next_hop != p->relay_node) { // Not already set
                         LOG_INFO("Update next hop of 0x%x to 0x%x based on ACK/reply (was relayer %d we were sole %d)", p->from,
                                  p->relay_node, wasAlreadyRelayer, weWereSoleRelayer);
                         origTx->next_hop = p->relay_node;
                     }
+                    noteRouteLearned(p->from, p->relay_node, millis()); // M3: anchor freshness (hot or overflow route)
+#if HAS_TRAFFIC_MANAGEMENT
+                    // Mirror the confirmed (and now unique-resolved) hop into the TMM overflow cache so it
+                    // survives even when the source isn't (or is no longer) in the hot NodeDB.
+                    if (trafficManagementModule)
+                        trafficManagementModule->setNextHop(p->from, p->relay_node);
+#endif
+                } else {
+                    LOG_DEBUG("Not learning next hop for 0x%x: relay byte 0x%x ambiguous/unknown; keep flooding", p->from,
+                              p->relay_node);
                 }
             }
         }
@@ -144,6 +161,11 @@ bool NextHopRouter::perhapsRebroadcast(const meshtastic_MeshPacket *p)
     if (!isToUs(p) && !isFromUs(p) && (p->hop_limit > 0 || exhaustHops)) {
         if (p->id != 0) {
             if (isRebroadcaster()) {
+                // NOTE: this is a self-identity match (is the addressed next_hop OUR last byte?), so it
+                // cannot be hardened with resolveLastByte() — a remote node that legitimately shares our
+                // last byte will also match here and rebroadcast. That residual collision needs a wider
+                // on-wire field to fix. M1/M2 instead shrink the blast radius by reducing how often an
+                // ambiguous next_hop byte is ever learned (sniffReceived) or originated (getNextHop).
                 if (p->next_hop == NO_NEXT_HOP_PREFERENCE || p->next_hop == nodeDB->getLastByteOfNodeNum(getNodeNum())) {
                     meshtastic_MeshPacket *tosend = packetPool.allocCopy(*p); // keep a copy because we will be sending it
                     LOG_INFO("Rebroadcast received message coming from %x", p->relay_node);
@@ -194,15 +216,63 @@ std::optional<uint8_t> NextHopRouter::getNextHop(NodeNum to, uint8_t relay_node)
     if (isBroadcast(to))
         return std::nullopt;
 
+    // Hot store first: a direct array hit on the live NodeDB entry.
     meshtastic_NodeInfoLite *node = nodeDB->getMeshNode(to);
     if (node && node->next_hop) {
+        // M3: proactively decay a stale or repeatedly-failing route back to flooding, so a dead hop
+        // isn't trusted on the next DM's first (and on dense meshes, slowest) attempt. We only act on
+        // a health record that still matches the stored byte; a next_hop set by another path (e.g.
+        // TraceRouteModule) with no matching record is left authoritative.
+        const RouteHealth *h = findRouteHealth(to);
+        if (h && h->lastNextHop == node->next_hop && isRouteStale(*h, millis())) {
+            LOG_INFO("Next hop 0x%x for 0x%x is stale (age/fails); flood and clear", node->next_hop, to);
+            node->next_hop = NO_NEXT_HOP_PREFERENCE; // clear persisted route
+            clearRouteHealth(to);                    // clear RAM health
+            return std::nullopt;
+        }
+
         // We are careful not to return the relay node as the next hop
         if (node->next_hop != relay_node) {
-            // LOG_DEBUG("Next hop for 0x%x is 0x%x", to, node->next_hop);
-            return node->next_hop;
+            // M1/M2: only emit a stored next_hop if its last byte still maps to a UNIQUE, currently
+            // reachable direct neighbor. On a dense mesh the last byte collides, so an ambiguous byte
+            // would unicast a hint toward the wrong physical node; if the neighbor has gone away we'd
+            // unicast into a void. In both cases flood instead (managed flooding still delivers).
+            ResolvedNode r = nodeDB->resolveLastByte(node->next_hop, /*requireDirectNeighbor=*/true);
+            if (r.status == LastByteResolution::Unique)
+                return node->next_hop;
+            LOG_WARN("Next hop 0x%x for 0x%x %s; set no pref", node->next_hop, to,
+                     r.status == LastByteResolution::Ambiguous ? "ambiguous among neighbors" : "not a known neighbor");
         } else
             LOG_WARN("Next hop for 0x%x is 0x%x, same as relayer; set no pref", to, node->next_hop);
     }
+
+#if HAS_TRAFFIC_MANAGEMENT
+    // Fallback: TMM overflow cache holds confirmed hops for nodes that have aged out of the hot store.
+    // It is the same byte source/confidence as NodeInfoLite.next_hop, so it gets the same M1/M2/M3
+    // protection: decay a stale/failing route, then only emit a byte that still resolves to a unique
+    // reachable neighbor. Without this the overflow cache (which holds MORE bytes for MORE nodes) would
+    // reintroduce exactly the silent-misroute that M1/M2 closes on the hot path.
+    if (trafficManagementModule) {
+        uint8_t hint = trafficManagementModule->getNextHopHint(to);
+        if (hint && hint != relay_node) {
+            const RouteHealth *h = findRouteHealth(to);
+            if (h && h->lastNextHop == hint && isRouteStale(*h, millis())) {
+                LOG_INFO("TMM next hop 0x%x for 0x%x is stale (age/fails); flood and clear", hint, to);
+                trafficManagementModule->clearNextHop(to); // clear overflow route (setNextHop won't store 0)
+                clearRouteHealth(to);                      // clear RAM health
+                return std::nullopt;
+            }
+            ResolvedNode r = nodeDB->resolveLastByte(hint, /*requireDirectNeighbor=*/true);
+            if (r.status == LastByteResolution::Unique) {
+                LOG_DEBUG("Next hop for 0x%x is 0x%x (TMM cache)", to, hint);
+                return hint;
+            }
+            LOG_WARN("TMM next hop 0x%x for 0x%x %s; set no pref", hint, to,
+                     r.status == LastByteResolution::Ambiguous ? "ambiguous among neighbors" : "not a known neighbor");
+        }
+    }
+#endif
+
     return std::nullopt;
 }
 
@@ -311,7 +381,10 @@ int32_t NextHopRouter::doRetransmissions()
 
                 if (!isBroadcast(p.packet->to)) {
                     if (p.numRetransmissions == 1) {
-                        // Last retransmission, reset next_hop (fallback to FloodingRouter)
+                        // Last retransmission: this directed delivery went un-ACKed. Record the failure
+                        // (M3 — accumulates across DMs to age out a flapping/dead route) and reset
+                        // next_hop so the final try falls back to FloodingRouter.
+                        noteRouteFailure(p.packet->to);
                         p.packet->next_hop = NO_NEXT_HOP_PREFERENCE;
                         // Also reset it in the nodeDB
                         meshtastic_NodeInfoLite *sentTo = nodeDB->getMeshNode(p.packet->to);
@@ -319,9 +392,32 @@ int32_t NextHopRouter::doRetransmissions()
                             LOG_INFO("Resetting next hop for packet with dest 0x%x\n", p.packet->to);
                             sentTo->next_hop = NO_NEXT_HOP_PREFERENCE;
                         }
+#if HAS_TRAFFIC_MANAGEMENT
+                        if (trafficManagementModule) {
+                            trafficManagementModule->clearNextHop(p.packet->to);
+                        }
+#endif
                         FloodingRouter::send(packetPool.allocCopy(*p.packet));
                     } else {
+#if NEXTHOP_EARLY_FLOOD_ON_UNVERIFIED
+                        // M4 (gated): if the route isn't proven healthy, don't spend a second directed
+                        // attempt — start flooding one retry sooner to cut recovery latency. A verified
+                        // route (fresh, zero recent failures) keeps the unchanged directed-retry path so
+                        // the sparse-mesh happy path is untouched.
+                        RouteHealth *h = findRouteHealth(p.packet->to);
+                        bool verified = h && h->consecutiveFailures == 0 && !isRouteStale(*h, now);
+                        if (!verified) {
+                            p.packet->next_hop = NO_NEXT_HOP_PREFERENCE;
+                            meshtastic_NodeInfoLite *sentTo = nodeDB->getMeshNode(p.packet->to);
+                            if (sentTo)
+                                sentTo->next_hop = NO_NEXT_HOP_PREFERENCE;
+                            FloodingRouter::send(packetPool.allocCopy(*p.packet));
+                        } else {
+                            NextHopRouter::send(packetPool.allocCopy(*p.packet));
+                        }
+#else
                         NextHopRouter::send(packetPool.allocCopy(*p.packet));
+#endif
                     }
                 } else {
                     // Note: we call the superclass version because we don't want to have our version of send() add a new
@@ -355,3 +451,96 @@ void NextHopRouter::setNextTx(PendingPacket *pending)
     printPacket("", pending->packet);
     setReceivedMessage(); // Run ASAP, so we can figure out our correct sleep time
 }
+
+// ---------------------------------------------------------------------------
+// M3: RAM route-health table. Bounded array with reuse-oldest eviction (same discipline as
+// PacketHistory). All age comparisons use unsigned subtraction so they survive the 49.7-day millis()
+// rollover. dest == 0 marks an empty slot; learnedAtMsec is normalized to 1 on write so an occupied
+// slot is never read as infinitely old.
+// ---------------------------------------------------------------------------
+
+RouteHealth *NextHopRouter::findRouteHealth(NodeNum dest)
+{
+    if (dest == 0)
+        return nullptr;
+    for (auto &h : routeHealth)
+        if (h.dest == dest)
+            return &h;
+    return nullptr;
+}
+
+RouteHealth *NextHopRouter::getOrAllocRouteHealth(NodeNum dest, uint32_t now)
+{
+    if (dest == 0)
+        return nullptr;
+
+    RouteHealth *oldest = &routeHealth[0];
+    RouteHealth *freeSlot = nullptr;
+    for (auto &h : routeHealth) {
+        if (h.dest == dest)
+            return &h; // existing record
+        if (h.dest == 0) {
+            if (!freeSlot)
+                freeSlot = &h; // remember the first free slot; prefer it over evicting
+            continue;
+        }
+        // Track the oldest occupied slot in case the table is full (rollover-safe).
+        if ((uint32_t)(now - h.learnedAtMsec) > (uint32_t)(now - oldest->learnedAtMsec))
+            oldest = &h;
+    }
+    // Claim the free slot if there is one, else reuse the oldest. Reset before use and stamp the dest
+    // so the record is findable.
+    RouteHealth *slot = freeSlot ? freeSlot : oldest;
+    *slot = RouteHealth{};
+    slot->dest = dest;
+    return slot;
+}
+
+void NextHopRouter::noteRouteLearned(NodeNum dest, uint8_t nextHop, uint32_t now)
+{
+    if (dest == 0 || nextHop == NO_NEXT_HOP_PREFERENCE)
+        return;
+    RouteHealth *h = getOrAllocRouteHealth(dest, now);
+    if (!h)
+        return;
+    // A genuinely new next hop earns a clean slate; re-learning the SAME hop keeps the accumulated
+    // failure count so an asymmetric reverse path that keeps re-teaching a dead forward hop still ages
+    // out instead of resetting the counter every time.
+    if (h->lastNextHop != nextHop) {
+        h->lastNextHop = nextHop;
+        h->consecutiveFailures = 0;
+    }
+    h->learnedAtMsec = now ? now : 1;
+}
+
+void NextHopRouter::noteRouteSuccess(NodeNum dest, uint32_t now)
+{
+    RouteHealth *h = findRouteHealth(dest);
+    if (!h)
+        return; // only routes we actually learned have health to refresh
+    h->consecutiveFailures = 0;
+    h->learnedAtMsec = now ? now : 1;
+}
+
+void NextHopRouter::noteRouteFailure(NodeNum dest)
+{
+    RouteHealth *h = findRouteHealth(dest);
+    if (!h)
+        return; // nothing to penalize (we were flooding, or never learned a route here)
+    if (h->consecutiveFailures < 255)
+        h->consecutiveFailures++;
+}
+
+bool NextHopRouter::isRouteStale(const RouteHealth &h, uint32_t now) const
+{
+    if (h.consecutiveFailures >= ROUTE_FAILURE_THRESHOLD)
+        return true;
+    return (uint32_t)(now - h.learnedAtMsec) >= ROUTE_TTL_MSEC;
+}
+
+void NextHopRouter::clearRouteHealth(NodeNum dest)
+{
+    RouteHealth *h = findRouteHealth(dest);
+    if (h)
+        *h = RouteHealth{};
+}

src/mesh/NextHopRouter.h

@@ -43,6 +43,28 @@ struct PendingPacket {
     explicit PendingPacket(meshtastic_MeshPacket *p, uint8_t numRetransmissions);
 };
 
+/**
+ * RAM-only per-destination route health. Tracks how fresh a learned next_hop is and how many
+ * consecutive directed deliveries to it have failed, so getNextHop() can proactively decay a stale or
+ * repeatedly-failing route back to flooding instead of trusting a dead hop on the next (and on dense
+ * meshes, slowest) attempt. Not persisted: the learned next_hop itself lives in NodeInfoLite; this is
+ * just freshness/failure metadata.
+ */
+struct RouteHealth {
+    NodeNum dest = 0;                             ///< destination this record describes; 0 == empty slot
+    uint32_t learnedAtMsec = 0;                   ///< millis() when next_hop was last (re)learned (rollover-aware)
+    uint8_t consecutiveFailures = 0;              ///< directed deliveries to `dest` that went un-ACKed
+    uint8_t lastNextHop = NO_NEXT_HOP_PREFERENCE; ///< the relay byte this health refers to
+};
+
+// M4 (optional, off by default): when a route is not proven healthy, fall back to flooding one retry
+// earlier instead of spending a second directed attempt. Trades airtime for recovery latency on dense
+// meshes; leaves the sparse-mesh happy path (fresh, verified routes) unchanged. Measure on the
+// simulator before enabling broadly.
+#ifndef NEXTHOP_EARLY_FLOOD_ON_UNVERIFIED
+#define NEXTHOP_EARLY_FLOOD_ON_UNVERIFIED 0
+#endif
+
 class GlobalPacketIdHashFunction
 {
   public:
@@ -92,12 +114,22 @@ class NextHopRouter : public FloodingRouter
     // The number of retransmissions the original sender will do
     constexpr static uint8_t NUM_RELIABLE_RETX = 3;
 
+    // M3: bounded RAM route-health table (reuse-oldest eviction, like PacketHistory)
+    constexpr static uint8_t ROUTE_HEALTH_MAX = 32;              // ~12B/slot -> ~384B
+    constexpr static uint32_t ROUTE_TTL_MSEC = 30UL * 60 * 1000; // re-discover a route unconfirmed for 30 min
+    constexpr static uint8_t ROUTE_FAILURE_THRESHOLD = 3;        // consecutive un-ACKed directed deliveries -> dead
+
   protected:
     /**
      * Pending retransmissions
      */
     std::unordered_map<GlobalPacketId, PendingPacket, GlobalPacketIdHashFunction> pending;
 
+    /**
+     * Per-destination route health (M3). Bounded array, reuse-oldest eviction. RAM-only.
+     */
+    RouteHealth routeHealth[ROUTE_HEALTH_MAX] = {};
+
     /**
      * Should this incoming filter be dropped?
      *
@@ -142,13 +174,38 @@ class NextHopRouter : public FloodingRouter
 
     void setNextTx(PendingPacket *pending);
 
+    // --- M3 route-health helpers (RAM-only). Protected so ReliableRouter (a subclass) can record
+    // delivery success, and so the unit-test shim can reach them via `using`. All take `now` where
+    // time matters so the decay logic is pure and testable without a clock mock. ---
+
+    /// @return the health record for `dest`, or nullptr if we hold none.
+    RouteHealth *findRouteHealth(NodeNum dest);
+    /// @return an existing record for `dest`, else a freshly claimed slot (reuse-oldest on overflow).
+    RouteHealth *getOrAllocRouteHealth(NodeNum dest, uint32_t now);
+    /// Record that we (re)learned `nextHop` for `dest`. Resets the failure count only when the hop
+    /// changed (so a flapping reverse-path re-learn of the same dead hop still ages out).
+    void noteRouteLearned(NodeNum dest, uint8_t nextHop, uint32_t now);
+    /// Record an end-to-end delivery success to `dest` (clears failures, refreshes freshness).
+    void noteRouteSuccess(NodeNum dest, uint32_t now);
+    /// Record that a directed delivery to `dest` went un-ACKed (no-op if we hold no record).
+    void noteRouteFailure(NodeNum dest);
+    /// @return true if the route is too old (TTL) or has failed too many times in a row.
+    bool isRouteStale(const RouteHealth &h, uint32_t now) const;
+    /// Forget any health record for `dest`.
+    void clearRouteHealth(NodeNum dest);
+
+#ifdef PIO_UNIT_TESTING
+  public: // expose getNextHop to the test shim without widening production visibility
+#else
   private:
+#endif
     /**
      * Get the next hop for a destination, given the relay node
      * @return the node number of the next hop, 0 if no preference (fallback to FloodingRouter)
      */
     std::optional<uint8_t> getNextHop(NodeNum to, uint8_t relay_node);
 
+  private:
     /** Check if we should be rebroadcasting this packet if so, do so.
      *  @return true if we did rebroadcast */
     bool perhapsRebroadcast(const meshtastic_MeshPacket *p) override;

src/mesh/NodeDB.h

@@ -11,6 +11,7 @@
 
 #include "MeshTypes.h"
 #include "NodeStatus.h"
+#include "WarmNodeStore.h"
 #include "concurrency/Lock.h"
 #include "configuration.h"
 #include "mesh-pb-constants.h"
@@ -114,6 +115,20 @@ uint32_t sinceLastSeen(const meshtastic_NodeInfoLite *n);
 /// Given a packet, return how many seconds in the past (vs now) it was received
 uint32_t sinceReceived(const meshtastic_MeshPacket *p);
 
+/// Outcome of mapping a single on-wire last-byte (next_hop / relay_node) back to a full NodeNum.
+/// Because the wire only carries the last byte of a 32-bit node number, the mapping is ambiguous on
+/// dense meshes (the "birthday problem"). Callers must treat Ambiguous and None as "don't trust it".
+enum class LastByteResolution : uint8_t {
+    None,      ///< no relevant candidate node has this last byte
+    Unique,    ///< exactly one relevant candidate -> `num` is valid
+    Ambiguous, ///< two or more relevant candidates collide on this byte
+};
+
+struct ResolvedNode {
+    LastByteResolution status = LastByteResolution::None;
+    NodeNum num = 0; ///< valid only when status == Unique
+};
+
 /// Given a packet, return the number of hops used to reach this node.
 /// Returns defaultIfUnknown if the number of hops couldn't be determined.
 int8_t getHopsAway(const meshtastic_MeshPacket &p, int8_t defaultIfUnknown = -1);
@@ -226,9 +241,25 @@ class NodeDB
     bool updateUser(uint32_t nodeId, meshtastic_User &p, uint8_t channelIndex = 0);
 
     /*
-     * Sets a node either favorite or unfavorite
+     * Sets a node either favorite or unfavorite. Returns true if the node ends
+     * up in the requested state; false if the node is unknown or favouriting
+     * was refused by the protected-node cap (MAX_NUM_NODES - 2).
      */
-    void set_favorite(bool is_favorite, uint32_t nodeId);
+    bool set_favorite(bool is_favorite, uint32_t nodeId);
+
+    /// Count of eviction-protected (favourite/ignored/manually-verified) nodes.
+    int numProtectedNodes() const;
+
+    /// printf-style warning emitted when setProtectedFlag() refuses a node at
+    /// the cap. %s = verb (favorite/ignore), 0x%08x = node, %d = cap. Shared by
+    /// LOG_WARN here and AdminModule::sendWarning so the wording stays in sync.
+    static constexpr const char *PROTECTED_CAP_WARN_FMT = "Can't %s 0x%08x: protected-node limit (%d) reached";
+
+    /// Turn an eviction-protection flag (favourite/ignored/verified) on/off. Off
+    /// always succeeds; on returns false (no change) once the protected set hits
+    /// the cap (MAX_NUM_NODES-2), keeping >=2 always-evictable slots. Callers
+    /// surface the refusal to the user.
+    bool setProtectedFlag(meshtastic_NodeInfoLite *node, uint32_t mask, bool on);
 
     /*
      * Returns true if the node is in the NodeDB and marked as favorite
@@ -295,6 +326,46 @@ class NodeDB
 
     virtual meshtastic_NodeInfoLite *getMeshNode(NodeNum n);
     size_t getNumMeshNodes() { return numMeshNodes; }
+    /// Find a node in our DB, create an empty NodeInfoLite if missing (evicting
+    /// the oldest non-protected node when full). Public so admin handlers can
+    /// register a node we have not heard from yet (e.g. to block it by ID).
+    meshtastic_NodeInfoLite *getOrCreateMeshNode(NodeNum n);
+
+#if WARM_NODE_COUNT > 0
+    // Warm ("long-tail") tier: minimal {num, last_heard, public_key} records
+    // for nodes evicted from the hot store. See WarmNodeStore.h.
+    WarmNodeStore warmStore;
+#endif
+
+    /// Copy the 32-byte public key for node n — hot store first, then the warm
+    /// tier. Returns false if we don't know a key for n.
+    bool copyPublicKey(NodeNum n, meshtastic_NodeInfoLite_public_key_t &out);
+
+    /// Resolve a node's device role — hot store (with user) first, then the role
+    /// cached in the warm tier, else CLIENT. Lets role-aware policy keep firing for
+    /// nodes that have aged out of the hot store.
+    meshtastic_Config_DeviceConfig_Role getNodeRole(NodeNum n);
+
+    /// last_heard of a hot-store node, or 0 if absent. Plain scan of meshNodes
+    /// with no allocation side effects (unlike getOrCreateMeshNode).
+    uint32_t hotNodeLastHeard(NodeNum n) const;
+
+    /**
+     * Resolve a single on-wire last-byte (e.g. next_hop / relay_node) back to a unique full NodeNum,
+     * detecting last-byte collisions instead of silently picking the first match. A 1-byte id only
+     * needs to be unique among a node's plausible relays, not the whole mesh, so we scope the search:
+     *  - requireDirectNeighbor == true  : candidates are direct neighbors (hops_away==0) heard within
+     *                                     NEXTHOP_NEIGHBOR_FRESH_SECS. Use on the SEND path.
+     *  - requireDirectNeighbor == false : also accept favorites and router-role nodes (unknown hop
+     *                                     distance allowed). Use when learning / preserving hops.
+     * Ignored nodes, our own node, and the broadcast/0 sentinels are never candidates. On a tie the
+     * result is Ambiguous (no tie-break) so callers fall back to flooding rather than misroute.
+     */
+    ResolvedNode resolveLastByte(uint8_t lastByte, bool requireDirectNeighbor);
+
+    /// Convenience wrapper around resolveLastByte(): true iff exactly one relevant candidate matches.
+    /// Ambiguous and None both return false (the safe answer for learning / hop preservation).
+    bool resolveUniqueLastByte(uint8_t lastByte, bool requireDirectNeighbor, NodeNum *outNum = nullptr);
 
     // Thread-safe satellite-map accessors. Return false if absent or the
     // corresponding DB is compiled out.
@@ -341,11 +412,15 @@ class NodeDB
         emptyNodeDatabase.version = DEVICESTATE_CUR_VER;
         size_t nodeDatabaseSize;
         pb_get_encoded_size(&nodeDatabaseSize, meshtastic_NodeDatabase_fields, &emptyNodeDatabase);
-        // Always include satellite slots so backups from higher-cap peers
-        // decode without truncation, even when our build excludes the DBs.
-        return nodeDatabaseSize + (MAX_NUM_NODES * meshtastic_NodeInfoLite_size) +
-               (MAX_NUM_NODES * meshtastic_NodePositionEntry_size) + (MAX_NUM_NODES * meshtastic_NodeTelemetryEntry_size) +
-               (MAX_NUM_NODES * meshtastic_NodeEnvironmentEntry_size) + (MAX_NUM_NODES * meshtastic_NodeStatusEntry_size);
+        // Decode-stream size ceiling only — no buffer this big is allocated (load
+        // streams from the file). Sized for the largest file any prior firmware
+        // could write (250-node ESP32-S3, satellites uncapped) so capacity
+        // downgrades / peer backups still decode; excess is trimmed after load.
+        // (not constexpr: portduino resolves MAX_NUM_NODES from runtime config)
+        const size_t loadCeiling = ((size_t)MAX_NUM_NODES > 250) ? (size_t)MAX_NUM_NODES : 250;
+        return nodeDatabaseSize + (loadCeiling * meshtastic_NodeInfoLite_size) +
+               (loadCeiling * meshtastic_NodePositionEntry_size) + (loadCeiling * meshtastic_NodeTelemetryEntry_size) +
+               (loadCeiling * meshtastic_NodeEnvironmentEntry_size) + (loadCeiling * meshtastic_NodeStatusEntry_size);
     }
 
     // returns true if the maximum number of nodes is reached or we are running low on memory
@@ -376,6 +451,12 @@ class NodeDB
     bool checkLowEntropyPublicKey(const meshtastic_Config_SecurityConfig_public_key_t &keyToTest);
 #endif
 
+    /// Consolidate crypto key generation logic used across multiple modules
+    /// @param privateKey Optional 32-byte private key to use. If nullptr, generates new random keys.
+    bool generateCryptoKeyPair(const uint8_t *privateKey = nullptr);
+
+    bool createNewIdentity();
+
     bool backupPreferences(meshtastic_AdminMessage_BackupLocation location);
     bool restorePreferences(meshtastic_AdminMessage_BackupLocation location,
                             int restoreWhat = SEGMENT_CONFIG | SEGMENT_MODULECONFIG | SEGMENT_DEVICESTATE | SEGMENT_CHANNELS);
@@ -388,15 +469,46 @@ class NodeDB
         newStatus.notifyObservers(&status);
     }
 
+#ifdef MESHTASTIC_ENCRYPTED_STORAGE
+    /// Re-run loadFromDisk() after the encrypted storage is unlocked at runtime.
+    /// Trigger: PhoneAPI::handleLockdownAuthInline sets lockdownReloadPending
+    /// on a successful provisionPassphrase / unlockWithPassphrase; the main
+    /// loop in main.cpp services the flag and calls this method on the main
+    /// thread. The transport callback stack (BLE/USB) is too small for the
+    /// file IO + MAX_NUM_NODES vector reserve + proto decode this triggers.
+    ///
+    /// Returns true iff every encrypted file decrypted and decoded cleanly.
+    /// On false the caller MUST treat the storage as corrupt: leave the
+    /// connection unauthenticated, emit a LOCKED(storage_corrupt) status,
+    /// and refuse to call setAdminAuthorized — otherwise a subsequent
+    /// set_config would re-encrypt a wrong baseline (the locked-default
+    /// values still resident in `config` / `channelFile` / `nodeDatabase`)
+    /// and overwrite the operator's persisted state.
+    bool reloadFromDisk();
+
+    /// Disable lockdown: decrypt every encrypted pref file back to plaintext,
+    /// then remove the DEK / token / counter / backoff artifacts. Requires
+    /// EncryptedStorage to be unlocked (DEK in RAM). Returns false if any
+    /// file failed to revert — in which case the DEK is still present and the
+    /// device remains in lockdown so the operator can retry. APPROTECT is not
+    /// reversed. Called from the main loop via lockdownDisablePending.
+    bool disableLockdownToPlaintext();
+
+    /// Set by loadProto when any encrypted file fails to decrypt or decode.
+    /// Tracked across an entire loadFromDisk pass so reloadFromDisk can
+    /// surface the condition without callers re-walking each loadProto
+    /// result. Cleared at the top of every loadFromDisk run.
+    bool storageCorruptThisLoad = false;
+#endif
+
   private:
     mutable concurrency::Lock satelliteMutex;
     bool duplicateWarned = false;
     bool localPositionUpdatedSinceBoot = false;
+    bool migrationSavePending = false;
     uint32_t lastNodeDbSave = 0;    // when we last saved our db to flash
     uint32_t lastBackupAttempt = 0; // when we last tried a backup automatically or manually
     uint32_t lastSort = 0;          // When last sorted the nodeDB
-    /// Find a node in our DB, create an empty NodeInfoLite if missing
-    meshtastic_NodeInfoLite *getOrCreateMeshNode(NodeNum n);
 
     /*
      * Internal boolean to track sorting paused
@@ -409,9 +521,33 @@ class NodeDB
     /// read our db from flash
     void loadFromDisk();
 
+#ifdef PIO_UNIT_TESTING
+    // Grant the unit-test shim access to the private maintenance paths below
+    // (migration / cleanup / eviction) without relaxing production access.
+    friend class NodeDBTestShim;
+#endif
+
     /// purge db entries without user info
     void cleanupMeshDB();
 
+    /// Trim each satellite map down to MAX_SATELLITE_NODES, dropping the
+    /// stalest entries (used after loading files written before the cap, or by
+    /// a build with a larger cap). Returns true iff anything was trimmed.
+    bool enforceSatelliteCaps();
+
+    /// Node-DB self-care; call only once identity is established (getNodeNum()
+    /// valid). Confirms self is present, trims/demotes only NON-self overflow, and
+    /// rewrites the store once when something changed (never while storage locked).
+    void nodeDBSelfCare();
+
+#if WARM_NODE_COUNT > 0
+    /// A database from a larger-cap build (e.g. the pre-fork 150-node nRF52 store)
+    /// can exceed MAX_NUM_NODES on load. Rank the hot store, demote the oldest
+    /// overflow into the warm tier preserving {num, last_heard, public_key} so PKI
+    /// DMs survive instead of dropping on truncation.
+    void demoteOldestHotNodesToWarm();
+#endif
+
     /// Reinit device state from scratch (not loading from disk)
     void installDefaultDeviceState(), installDefaultNodeDatabase(), installDefaultChannels(),
         installDefaultConfig(bool preserveKey), installDefaultModuleConfig();
@@ -487,7 +623,9 @@ extern uint32_t error_address;
 #define NODEINFO_BITFIELD_IS_UNMESSAGABLE_MASK (1u << NODEINFO_BITFIELD_IS_UNMESSAGABLE_SHIFT)
 #define NODEINFO_BITFIELD_HAS_IS_UNMESSAGABLE_SHIFT 8
 #define NODEINFO_BITFIELD_HAS_IS_UNMESSAGABLE_MASK (1u << NODEINFO_BITFIELD_HAS_IS_UNMESSAGABLE_SHIFT)
-// Bits 9..31 reserved for future single-bit flags.
+#define NODEINFO_BITFIELD_HAS_XEDDSA_SIGNED_SHIFT 9
+#define NODEINFO_BITFIELD_HAS_XEDDSA_SIGNED_MASK (1u << NODEINFO_BITFIELD_HAS_XEDDSA_SIGNED_SHIFT)
+// Bits 10..31 reserved for future single-bit flags.
 
 // Convenience accessors so call sites read like the old struct fields.
 inline bool nodeInfoLiteHasUser(const meshtastic_NodeInfoLite *n)
@@ -526,6 +664,16 @@ inline bool nodeInfoLiteIsKeyManuallyVerified(const meshtastic_NodeInfoLite *n)
 {
     return n && (n->bitfield & NODEINFO_BITFIELD_IS_KEY_MANUALLY_VERIFIED_MASK);
 }
+inline bool nodeInfoLiteHasXeddsaSigned(const meshtastic_NodeInfoLite *n)
+{
+    return n && (n->bitfield & NODEINFO_BITFIELD_HAS_XEDDSA_SIGNED_MASK);
+}
+/// A node that the eviction/migration paths must not drop: a favourite, an
+/// ignored (blocked) node, or a manually-verified key.
+inline bool nodeInfoLiteIsProtected(const meshtastic_NodeInfoLite *n)
+{
+    return nodeInfoLiteIsFavorite(n) || nodeInfoLiteIsIgnored(n) || nodeInfoLiteIsKeyManuallyVerified(n);
+}
 
 inline void nodeInfoLiteSetBit(meshtastic_NodeInfoLite *n, uint32_t mask, bool value)
 {

src/mesh/NodeDBLegacyMigration.cpp

@@ -14,6 +14,7 @@
 #include "configuration.h"
 #include "mesh-pb-constants.h"
 #include "mesh/generated/meshtastic/deviceonly_legacy.pb.h"
+#include "meshUtils.h"
 
 #include <algorithm>
 #include <cstring>
@@ -88,8 +89,10 @@ bool NodeDB::migrateLegacyNodeDatabase()
                 slim.bitfield |= NODEINFO_BITFIELD_HAS_USER_MASK;
                 strncpy(slim.long_name, legacy.user.long_name, sizeof(slim.long_name));
                 slim.long_name[sizeof(slim.long_name) - 1] = '\0';
+                sanitizeUtf8(slim.long_name, sizeof(slim.long_name)); // replace bad bytes so nanopb encode never fails
                 strncpy(slim.short_name, legacy.user.short_name, sizeof(slim.short_name));
                 slim.short_name[sizeof(slim.short_name) - 1] = '\0';
+                sanitizeUtf8(slim.short_name, sizeof(slim.short_name)); // same — v24 names may contain non-UTF-8 bytes
                 slim.hw_model = legacy.user.hw_model;
                 slim.role = legacy.user.role;
                 if (legacy.user.is_licensed)

src/mesh/PacketHistory.cpp

@@ -486,7 +486,11 @@ bool PacketHistory::wasRelayer(const uint8_t relayer, const uint32_t id, const N
 }
 
 /* Check if a certain node was a relayer of a packet in the history given iterator
- * @return true if node was indeed a relayer, false if not */
+ * @return true if node was indeed a relayer, false if not
+ * NOTE: intentionally byte-domain. Both `relayer` and relayed_by[] are on-wire last bytes, so this
+ * answers "did a relayer with this byte touch the packet" — correct without resolving to a NodeNum.
+ * The collision risk is neutralized where the result is consumed (route learning in
+ * NextHopRouter::sniffReceived now gates the write through NodeDB::resolveUniqueLastByte). */
 bool PacketHistory::wasRelayer(const uint8_t relayer, const PacketRecord &r, bool *wasSole)
 {
     bool found = false;

src/mesh/PhoneAPI.cpp

@@ -3,9 +3,16 @@
 #include "GPS.h"
 #endif
 
+#ifdef MESHTASTIC_ENCRYPTED_STORAGE
+#include "security/EncryptedStorage.h"
+#endif
+#ifdef MESHTASTIC_LOCKDOWN
+#include "security/LockdownDisplay.h"
+#endif
 #include "Channels.h"
 #include "Default.h"
 #include "FSCommon.h"
+#include "MeshRadio.h"
 #include "MeshService.h"
 #include "NodeDB.h"
 #include "PacketHistory.h"
@@ -36,6 +43,194 @@
 // Flag to indicate a heartbeat was received and we should send queue status
 bool heartbeatReceived = false;
 
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+// Auth-slot table and status-slot table are both sized to the typical
+// SerialConsole + BluetoothPhoneAPI footprint plus room for WiFi/TCP
+// transports. Sized together so both tables are keyed identically.
+static constexpr size_t MAX_AUTH_SLOTS = 6;
+
+// Per-PhoneAPI pending LockdownStatus. One slot per connection so a
+// status produced for connection A (e.g. UNLOCKED with the active TTL,
+// or UNLOCK_FAILED with a backoff) cannot be drained by connection B,
+// which would otherwise learn that A just authenticated or just failed
+// — a real information leak across local clients.
+//
+// File-scope rather than a per-PhoneAPI member because adding any
+// non-trivial state directly to PhoneAPI broke USB-CDC enumeration on
+// the current nRF52 framework; the auth-slot table next door uses the
+// same workaround. Lifecycle is tied to the auth slot table — both are
+// keyed by PhoneAPI*, both are cleared together in clearAuthSlot_LH,
+// and both share g_authSlotsMutex.
+struct PendingStatusSlot {
+    PhoneAPI *who = nullptr;
+    meshtastic_LockdownStatus status = {};
+    bool hasPending = false;
+    // True between a successful passphrase verify and the main-loop
+    // reloadFromDisk that follows. While set, the connection is NOT
+    // yet authorized and no UNLOCKED status has been emitted — the
+    // client still sees LOCKED, and any admin op it tries is dropped
+    // by the existing unauth gates. Cleared either way by
+    // completePendingUnlocks once reload finishes.
+    bool pendingUnlockAfterReload = false;
+};
+static PendingStatusSlot g_statusSlots[MAX_AUTH_SLOTS];
+
+// Lock-held helpers ---------------------------------------------------------
+
+static PendingStatusSlot *findOrAllocStatusSlot_LH(PhoneAPI *p)
+{
+    if (!p)
+        return nullptr;
+    for (auto &s : g_statusSlots)
+        if (s.who == p)
+            return &s;
+    for (auto &s : g_statusSlots) {
+        if (s.who == nullptr) {
+            s.who = p;
+            s.hasPending = false;
+            s.pendingUnlockAfterReload = false;
+            memset(&s.status, 0, sizeof(s.status));
+            return &s;
+        }
+    }
+    // Mirror the auth-slot eviction policy: stale slots can be reused.
+    // A connection that lost its auth slot has nothing meaningful to be
+    // told via a pending status anyway. Never evict a slot mid-unlock
+    // (pendingUnlockAfterReload set) — completing that flow on the
+    // wrong PhoneAPI would authorize the wrong connection.
+    for (auto &s : g_statusSlots) {
+        if (!s.hasPending && !s.pendingUnlockAfterReload) {
+            s.who = p;
+            memset(&s.status, 0, sizeof(s.status));
+            return &s;
+        }
+    }
+    return nullptr;
+}
+
+static void clearStatusSlot_LH(const PhoneAPI *p)
+{
+    if (!p)
+        return;
+    for (auto &s : g_statusSlots) {
+        if (s.who == p) {
+            s.who = nullptr;
+            s.hasPending = false;
+            s.pendingUnlockAfterReload = false;
+            memset(&s.status, 0, sizeof(s.status));
+            return;
+        }
+    }
+}
+
+// Build a LockdownStatus message under lock from the supplied fields,
+// applying the audit's M13 redaction so token_* tamper-detection
+// strings are not leaked to unauth clients over the wire.
+static void buildStatus_LH(meshtastic_LockdownStatus &out, meshtastic_LockdownStatus_State state, const char *lock_reason,
+                           uint8_t boots_remaining, uint32_t valid_until_epoch, uint32_t backoff_seconds)
+{
+    memset(&out, 0, sizeof(out));
+    out.state = state;
+    // Collapse the specific token_* reasons to a generic "locked" over
+    // the wire — full detail still goes to local logs. An unauth client
+    // does not need to know whether HMAC failed vs the boot count
+    // hit zero vs the file was the wrong size; all of those mean the
+    // same thing to the client ("locked, ask for passphrase") but
+    // telling them apart over the network lets an attacker confirm
+    // that their tampering or rollback attempt was noticed.
+    const char *wireReason = lock_reason;
+    if (state == meshtastic_LockdownStatus_State_LOCKED && wireReason && wireReason[0] != '\0') {
+        if (strncmp(wireReason, "token_", 6) == 0)
+            wireReason = "locked";
+    }
+    if (wireReason && wireReason[0] != '\0')
+        strncpy(out.lock_reason, wireReason, sizeof(out.lock_reason) - 1);
+    out.boots_remaining = boots_remaining;
+    out.valid_until_epoch = valid_until_epoch;
+    out.backoff_seconds = backoff_seconds;
+}
+
+// Per-connection auth state table keyed by PhoneAPI*. Searched linearly;
+// cost is negligible compared to the redaction gates that call it.
+struct PhoneAuthSlot {
+    PhoneAPI *who = nullptr;
+    bool authorized = false;
+    uint32_t epoch = 0;
+};
+static PhoneAuthSlot g_authSlots[MAX_AUTH_SLOTS];
+
+// Global auth epoch. Lock Now bumps it; per-slot `epoch` compared against
+// this. Wraps at 2^32 revocations — practically unreachable; on wrap the
+// only behavioral effect is that any slot whose epoch happens to match the
+// new low value would be treated as authorized again, which requires a
+// pre-existing authorized slot to survive 2^32 lockNow events on the same
+// boot.
+static uint32_t g_authEpoch = 1;
+
+// Single mutex guarding g_authSlots and g_authEpoch. All readers and
+// writers — including const getters like getAdminAuthorized — must take
+// it. Granularity is fine because the critical sections are short (a
+// fixed-size linear scan over 6 entries) and contention is dominated by
+// getFromRadio's per-call redaction checks, which tolerate brief
+// blocking.
+static concurrency::Lock g_authSlotsMutex;
+
+// Find or allocate the auth slot for `p`. Caller must hold g_authSlotsMutex.
+// When the table is full of *unauthorized* slots from prior dead PhoneAPIs,
+// evicts the first unauthorized slot found. Refuses to evict an authorized
+// slot (those represent a live operator session and must outlive the table
+// pressure of reconnect churn). Returns nullptr only if every slot is
+// occupied by a different live, authorized PhoneAPI — practically only
+// reachable as a DoS via 7+ simultaneous authed connections, in which
+// case fail-closed and log.
+static PhoneAuthSlot *findOrAllocSlot_LH(PhoneAPI *p)
+{
+    if (!p)
+        return nullptr;
+    for (auto &s : g_authSlots)
+        if (s.who == p)
+            return &s;
+    // First pass: free (who==nullptr) slot.
+    for (auto &s : g_authSlots) {
+        if (s.who == nullptr) {
+            s.who = p;
+            s.authorized = false;
+            s.epoch = 0;
+            return &s;
+        }
+    }
+    // Second pass: evict an unauthorized stale slot. Don't touch authorized
+    // ones — those still represent an operator-authenticated session.
+    for (auto &s : g_authSlots) {
+        if (!s.authorized) {
+            s.who = p;
+            s.epoch = 0;
+            LOG_WARN("Lockdown: auth slot table full, evicted stale unauthorized slot for new PhoneAPI %p", p);
+            return &s;
+        }
+    }
+    LOG_WARN("Lockdown: auth slot table full of authorized sessions, refusing new PhoneAPI %p (fail-closed)", p);
+    return nullptr;
+}
+
+// Drop p's slot from both the auth table and the status-queue table.
+// Lock-held variant.
+static void clearAuthSlot_LH(const PhoneAPI *p)
+{
+    if (!p)
+        return;
+    for (auto &s : g_authSlots) {
+        if (s.who == p) {
+            s.authorized = false;
+            s.epoch = 0;
+            s.who = nullptr;
+            break;
+        }
+    }
+    clearStatusSlot_LH(p);
+}
+#endif
+
 PhoneAPI::PhoneAPI()
 {
     lastContactMsec = millis();
@@ -45,6 +240,17 @@ PhoneAPI::PhoneAPI()
 PhoneAPI::~PhoneAPI()
 {
     close();
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+    // Free the auth slot unconditionally, regardless of whether close()'s
+    // slot-clear branch ran (it skips when state == STATE_SEND_NOTHING).
+    // Leaving a stale slot.who pointing at freed memory lets a future
+    // PhoneAPI heap-allocated at the same address inherit the prior
+    // session's authorization through findOrAllocSlot.
+    {
+        concurrency::LockGuard g(&g_authSlotsMutex);
+        clearAuthSlot_LH(this);
+    }
+#endif
 }
 
 void PhoneAPI::handleStartConfig()
@@ -55,6 +261,28 @@ void PhoneAPI::handleStartConfig()
         observe(&service->fromNumChanged);
 #ifdef FSCom
         observe(&xModem.packetReady);
+#endif
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+        // New physical connection: clear this PhoneAPI's auth slot so the new
+        // client must present a passphrase or PKC admin signature before
+        // seeing full config. Do NOT reset on a subsequent want_config_id
+        // within the same connection: after a successful unlock the client
+        // re-requests config to pull the now-unredacted values, and re-locking
+        // that same-link re-fetch would strip the auth it just earned (config
+        // comes back redacted and set_config writes get dropped).
+        //
+        // The security boundary is therefore the physical connection, not the
+        // want_config handshake. For BLE that boundary is enforced in
+        // onConnect() (which fires once per link and also resets the slot), so
+        // a reconnect re-locks even if this !isConnected() transition was
+        // missed because the prior link's close() raced the new config burst.
+        {
+            concurrency::LockGuard g(&g_authSlotsMutex);
+            if (auto *slot = findOrAllocSlot_LH(this)) {
+                slot->authorized = false;
+                slot->epoch = 0;
+            }
+        }
 #endif
     }
 
@@ -157,6 +385,12 @@ void PhoneAPI::close()
         config_state = 0;
         pauseBluetoothLogging = false;
         heartbeatReceived = false;
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+        {
+            concurrency::LockGuard g(&g_authSlotsMutex);
+            clearAuthSlot_LH(this);
+        }
+#endif
     }
 }
 
@@ -185,6 +419,26 @@ bool PhoneAPI::handleToRadio(const uint8_t *buf, size_t bufLength)
     if (pb_decode_from_bytes(buf, bufLength, &meshtastic_ToRadio_msg, &toRadioScratch)) {
         switch (toRadioScratch.which_payload_variant) {
         case meshtastic_ToRadio_packet_tag:
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                // Allow admin messages addressed to this device — passphrase delivery must get through.
+                // AdminModule handles its own is_managed gate for those.
+                // Block everything else — unauthorized clients cannot inject mesh traffic.
+                // Require the packet to carry a decoded (not encrypted) payload so portnum is valid.
+                // Refuse to match when our own node number is still 0 (NodeDB
+                // not yet loaded — happens during the locked-default boot path
+                // before reloadFromDisk). Otherwise a packet with to==0 would
+                // satisfy the equality and bypass the gate.
+                NodeNum ourNum = nodeDB->getNodeNum();
+                bool isLocalAdmin =
+                    ourNum != 0 && toRadioScratch.packet.which_payload_variant == meshtastic_MeshPacket_decoded_tag &&
+                    toRadioScratch.packet.decoded.portnum == meshtastic_PortNum_ADMIN_APP && toRadioScratch.packet.to == ourNum;
+                if (!isLocalAdmin) {
+                    LOG_INFO("Lockdown: Dropping non-admin ToRadio packet from unauthorized client");
+                    return false;
+                }
+            }
+#endif
             return handleToRadioPacket(toRadioScratch.packet);
         case meshtastic_ToRadio_want_config_id_tag:
             config_nonce = toRadioScratch.want_config_id;
@@ -196,6 +450,12 @@ bool PhoneAPI::handleToRadio(const uint8_t *buf, size_t bufLength)
             close();
             break;
         case meshtastic_ToRadio_xmodemPacket_tag:
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                LOG_INFO("Lockdown: Dropping xmodem packet from unauthorized client");
+                break;
+            }
+#endif
             LOG_INFO("Got xmodem packet");
 #ifdef FSCom
             xModem.handlePacket(toRadioScratch.xmodemPacket);
@@ -257,9 +517,10 @@ bool PhoneAPI::handleToRadio(const uint8_t *buf, size_t bufLength)
     STATE_SEND_UIDATA,
     STATE_SEND_OWN_NODEINFO,
     STATE_SEND_METADATA,
-    STATE_SEND_CHANNELS
+    STATE_SEND_REGION_PRESETS, // region -> valid modem presets (one message)
+    STATE_SEND_CHANNELS,
     STATE_SEND_CONFIG,
-    STATE_SEND_MODULE_CONFIG,
+    STATE_SEND_MODULECONFIG,
     STATE_SEND_OTHER_NODEINFOS, // states progress in this order as the device sends to the client
     STATE_SEND_FILEMANIFEST,
     STATE_SEND_COMPLETE_ID,
@@ -298,6 +559,21 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
         strncpy(myNodeInfo.pio_env, optstr(APP_ENV), sizeof(myNodeInfo.pio_env));
         myNodeInfo.nodedb_count = static_cast<uint16_t>(nodeDB->getNumMeshNodes());
         fromRadioScratch.my_info = myNodeInfo;
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+        if (!getAdminAuthorized()) {
+            // device_id is a stable hardware identifier — useful for an attacker
+            // to fingerprint / correlate the device across observations. Strip it
+            // for unauthenticated clients. my_node_num is kept (it's broadcast
+            // on the mesh anyway). pio_env / min_app_version reveal the exact
+            // build flavour, useful only for picking which known-CVE to try.
+            // nodedb_count stays — clients need it to decide whether to pull
+            // the node DB after unlocking.
+            fromRadioScratch.my_info.device_id.size = 0;
+            memset(fromRadioScratch.my_info.device_id.bytes, 0, sizeof(fromRadioScratch.my_info.device_id.bytes));
+            memset(fromRadioScratch.my_info.pio_env, 0, sizeof(fromRadioScratch.my_info.pio_env));
+            fromRadioScratch.my_info.min_app_version = 0;
+        }
+#endif
         state = STATE_SEND_UIDATA;
 
         service->refreshLocalMeshNode(); // Update my NodeInfo because the client will be asking for it soon.
@@ -331,8 +607,15 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
         }
         if (config_nonce == SPECIAL_NONCE_ONLY_NODES) {
             // If client only wants node info, jump directly to sending nodes
-            state = STATE_SEND_OTHER_NODEINFOS;
-            onNowHasData(0);
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                state = STATE_SEND_COMPLETE_ID; // Unauthorized: skip node DB
+            } else
+#endif
+            {
+                state = STATE_SEND_OTHER_NODEINFOS;
+                onNowHasData(0);
+            }
         } else {
             state = STATE_SEND_METADATA;
         }
@@ -343,12 +626,48 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
         LOG_DEBUG("Send device metadata");
         fromRadioScratch.which_payload_variant = meshtastic_FromRadio_metadata_tag;
         fromRadioScratch.metadata = getDeviceMetadata();
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+        if (!getAdminAuthorized()) {
+            // DeviceMetadata is one large fingerprint vector for an unauth
+            // client: firmware_version, device_state_version, hw_model,
+            // hw_model_string, has_bluetooth/has_wifi/has_ethernet, role,
+            // position_flags, excluded_modules, optionsCount. None of it
+            // is needed to drive lockdown_auth, and most of it tells an
+            // attacker which CVE / behavior quirks to probe. Wipe the
+            // whole struct — clients re-fetch once authenticated.
+            memset(&fromRadioScratch.metadata, 0, sizeof(fromRadioScratch.metadata));
+        }
+#endif
+        state = STATE_SEND_REGION_PRESETS;
+        break;
+
+    case STATE_SEND_REGION_PRESETS:
+        // Tell the client which modem presets are legal in each region so its UI
+        // can block illegal region+preset combinations. This is public RF /
+        // regulatory information (region and modem_preset are already in the
+        // unauthenticated LoRa whitelist below), so it is sent unconditionally —
+        // even an unauthorized/locked-down client can render a correct picker.
+        LOG_DEBUG("Send region preset map");
+        fromRadioScratch.which_payload_variant = meshtastic_FromRadio_region_presets_tag;
+        getRegionPresetMap(fromRadioScratch.region_presets);
         state = STATE_SEND_CHANNELS;
+        config_state = 0; // STATE_SEND_CHANNELS indexes channels starting at 0
         break;
 
     case STATE_SEND_CHANNELS:
         fromRadioScratch.which_payload_variant = meshtastic_FromRadio_channel_tag;
-        fromRadioScratch.channel = channels.getByIndex(config_state);
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+        if (!getAdminAuthorized()) {
+            // Unauthenticated: emit a zero-initialized Channel. fromRadioScratch
+            // was memset(0) at the top of getFromRadio(), so leaving .channel
+            // untouched gives the client an empty entry — no name, no PSK, no
+            // role. Advances the state machine normally so config_complete_id
+            // still fires.
+        } else
+#endif
+        {
+            fromRadioScratch.channel = channels.getByIndex(config_state);
+        }
         config_state++;
         // Advance when we have sent all of our Channels
         if (config_state >= MAX_NUM_CHANNELS) {
@@ -380,7 +699,15 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
         case meshtastic_Config_network_tag:
             LOG_DEBUG("Send config: network");
             fromRadioScratch.config.which_payload_variant = meshtastic_Config_network_tag;
-            fromRadioScratch.config.payload_variant.network = config.network;
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                // Unauthenticated: emit an empty NetworkConfig (zero-init from the
+                // top-of-loop memset). No wifi_psk, no SSID, no static IP info.
+            } else
+#endif
+            {
+                fromRadioScratch.config.payload_variant.network = config.network;
+            }
             break;
         case meshtastic_Config_display_tag:
             LOG_DEBUG("Send config: display");
@@ -390,7 +717,28 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
         case meshtastic_Config_lora_tag:
             LOG_DEBUG("Send config: lora");
             fromRadioScratch.config.which_payload_variant = meshtastic_Config_lora_tag;
-            fromRadioScratch.config.payload_variant.lora = config.lora;
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                // Whitelist only the spec-mandated radio identity fields that
+                // are intrinsically observable on the air anyway: region,
+                // modem_preset, use_preset, channel_num, hop_limit. Operator-
+                // private knobs (ignore_incoming list, override_duty_cycle,
+                // override_frequency, sx126x_rx_boosted_gain, tx_power,
+                // ignore_mqtt, fem_lna_mode, config_ok_to_mqtt, ...) stay
+                // hidden — they tell an attacker how the operator has tuned
+                // the device but are not needed by an unauth client.
+                meshtastic_Config_LoRaConfig whitelist = {};
+                whitelist.use_preset = config.lora.use_preset;
+                whitelist.modem_preset = config.lora.modem_preset;
+                whitelist.region = config.lora.region;
+                whitelist.channel_num = config.lora.channel_num;
+                whitelist.hop_limit = config.lora.hop_limit;
+                fromRadioScratch.config.payload_variant.lora = whitelist;
+            } else
+#endif
+            {
+                fromRadioScratch.config.payload_variant.lora = config.lora;
+            }
             break;
         case meshtastic_Config_bluetooth_tag:
             LOG_DEBUG("Send config: bluetooth");
@@ -400,7 +748,21 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
         case meshtastic_Config_security_tag:
             LOG_DEBUG("Send config: security");
             fromRadioScratch.config.which_payload_variant = meshtastic_Config_security_tag;
-            fromRadioScratch.config.payload_variant.security = config.security;
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                // Unauthenticated: emit an empty SecurityConfig (zero-init from
+                // the top-of-loop memset). No private_key, no admin_keys, no
+                // public_key — nothing for an attacker to inspect.
+                //
+                // Provisioning state (NEEDS_PROVISION vs LOCKED) is conveyed via
+                // the FromRadio.lockdown_status proto sent post-config; clients
+                // should consume that rather than inferring from this empty
+                // security config.
+            } else
+#endif
+            {
+                fromRadioScratch.config.payload_variant.security = config.security;
+            }
             break;
         case meshtastic_Config_sessionkey_tag:
             LOG_DEBUG("Send config: sessionkey");
@@ -430,7 +792,17 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
         case meshtastic_ModuleConfig_mqtt_tag:
             LOG_DEBUG("Send module config: mqtt");
             fromRadioScratch.moduleConfig.which_payload_variant = meshtastic_ModuleConfig_mqtt_tag;
-            fromRadioScratch.moduleConfig.payload_variant.mqtt = moduleConfig.mqtt;
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                // Unauthenticated: emit an empty MQTTConfig (zero-init from
+                // the top-of-loop memset). MQTT broker username/password, the
+                // server address, and root_topic are credentials/config that
+                // shouldn't be visible to an unauth client.
+            } else
+#endif
+            {
+                fromRadioScratch.moduleConfig.payload_variant.mqtt = moduleConfig.mqtt;
+            }
             break;
         case meshtastic_ModuleConfig_serial_tag:
             LOG_DEBUG("Send module config: serial");
@@ -509,15 +881,21 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
         config_state++;
         // Advance when we have sent all of our ModuleConfig objects
         if (config_state > (_meshtastic_AdminMessage_ModuleConfigType_MAX + 1)) {
-            // Handle special nonce behaviors:
-            // - SPECIAL_NONCE_ONLY_CONFIG: Skip node info, go directly to file manifest
-            // - SPECIAL_NONCE_ONLY_NODES: After sending nodes, skip to complete
-            if (config_nonce == SPECIAL_NONCE_ONLY_CONFIG) {
-                state = STATE_SEND_FILEMANIFEST;
-            } else {
-                state = STATE_SEND_OTHER_NODEINFOS;
-                onNowHasData(0);
-            }
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                // Unauthorized client: skip node DB and file manifest — only send config complete
+                state = STATE_SEND_COMPLETE_ID;
+            } else
+#endif
+                // Handle special nonce behaviors:
+                // - SPECIAL_NONCE_ONLY_CONFIG: Skip node info, go directly to file manifest
+                // - SPECIAL_NONCE_ONLY_NODES: After sending nodes, skip to complete
+                if (config_nonce == SPECIAL_NONCE_ONLY_CONFIG) {
+                    state = STATE_SEND_FILEMANIFEST;
+                } else {
+                    state = STATE_SEND_OTHER_NODEINFOS;
+                    onNowHasData(0);
+                }
             config_state = 0;
         }
         break;
@@ -590,24 +968,58 @@ size_t PhoneAPI::getFromRadio(uint8_t *buf)
             fromRadioScratch.queueStatus = *queueStatusPacketForPhone;
             releaseQueueStatusPhonePacket();
         } else if (mqttClientProxyMessageForPhone) {
-            fromRadioScratch.which_payload_variant = meshtastic_FromRadio_mqttClientProxyMessage_tag;
-            fromRadioScratch.mqttClientProxyMessage = *mqttClientProxyMessageForPhone;
-            releaseMqttClientProxyPhonePacket();
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                releaseMqttClientProxyPhonePacket(); // Discard — unauthorized client
+            } else
+#endif
+            {
+                fromRadioScratch.which_payload_variant = meshtastic_FromRadio_mqttClientProxyMessage_tag;
+                fromRadioScratch.mqttClientProxyMessage = *mqttClientProxyMessageForPhone;
+                releaseMqttClientProxyPhonePacket();
+            }
         } else if (xmodemPacketForPhone.control != meshtastic_XModem_Control_NUL) {
-            fromRadioScratch.which_payload_variant = meshtastic_FromRadio_xmodemPacket_tag;
-            fromRadioScratch.xmodemPacket = xmodemPacketForPhone;
-            xmodemPacketForPhone = meshtastic_XModem_init_zero;
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                xmodemPacketForPhone = meshtastic_XModem_init_zero; // Discard — unauthorized client
+            } else
+#endif
+            {
+                fromRadioScratch.which_payload_variant = meshtastic_FromRadio_xmodemPacket_tag;
+                fromRadioScratch.xmodemPacket = xmodemPacketForPhone;
+                xmodemPacketForPhone = meshtastic_XModem_init_zero;
+            }
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+        } else if (hasPendingLockdownStatus()) {
+            concurrency::LockGuard guard(&g_authSlotsMutex);
+            // Look up our own slot only — never another connection's. Re-check
+            // hasPending under the lock since a concurrent drain on the same
+            // connection (unlikely but possible if multiple transport
+            // callbacks race against one PhoneAPI) may have grabbed it.
+            if (auto *slot = findOrAllocStatusSlot_LH(this); slot && slot->hasPending) {
+                fromRadioScratch.which_payload_variant = meshtastic_FromRadio_lockdown_status_tag;
+                fromRadioScratch.lockdown_status = slot->status;
+                memset(&slot->status, 0, sizeof(slot->status));
+                slot->hasPending = false;
+            }
+#endif
         } else if (clientNotification) {
             fromRadioScratch.which_payload_variant = meshtastic_FromRadio_clientNotification_tag;
             fromRadioScratch.clientNotification = *clientNotification;
             releaseClientNotification();
         } else if (packetForPhone) {
-            printPacket("phone downloaded packet", packetForPhone);
-
-            // Encapsulate as a FromRadio packet
-            fromRadioScratch.which_payload_variant = meshtastic_FromRadio_packet_tag;
-            fromRadioScratch.packet = *packetForPhone;
-            releasePhonePacket();
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+            if (!getAdminAuthorized()) {
+                releasePhonePacket(); // Discard mesh traffic — unauthorized client
+            } else
+#endif
+            {
+                printPacket("phone downloaded packet", packetForPhone);
+                // Encapsulate as a FromRadio packet
+                fromRadioScratch.which_payload_variant = meshtastic_FromRadio_packet_tag;
+                fromRadioScratch.packet = *packetForPhone;
+                releasePhonePacket();
+            }
         } else if (replayPending()) {
             // No live packet pending — feed the phone one cached satellite-DB packet.
             // popReplayPacket advances through positions->telemetry->environment->status,
@@ -669,6 +1081,29 @@ void PhoneAPI::sendConfigComplete()
         service->api_state = service->STATE_ETH;
     }
 
+#if defined(MESHTASTIC_ENCRYPTED_STORAGE) && defined(MESHTASTIC_PHONEAPI_ACCESS_CONTROL)
+    if (!EncryptedStorage::isLockdownActive()) {
+        // Lockdown-capable firmware, but lockdown is not active on this
+        // device (never provisioned, or disabled). Tell the client so its
+        // "lockdown mode" toggle renders OFF. Note getAdminAuthorized()
+        // returns true in this state, so the redaction gates are no-ops and
+        // the client just received the full, unredacted config above.
+        queueLockdownStatus(meshtastic_LockdownStatus_State_DISABLED, "", 0, 0, 0);
+        LOG_INFO("PhoneAPI: DISABLED (lockdown not active) sent to client");
+    } else if (!getAdminAuthorized()) {
+        if (!EncryptedStorage::isProvisioned()) {
+            queueLockdownStatus(meshtastic_LockdownStatus_State_NEEDS_PROVISION, "", 0, 0, 0);
+            LOG_INFO("PhoneAPI: NEEDS_PROVISION sent to client");
+        } else if (!EncryptedStorage::isUnlocked()) {
+            queueLockdownStatus(meshtastic_LockdownStatus_State_LOCKED, EncryptedStorage::getLockReason(), 0, 0, 0);
+            LOG_INFO("PhoneAPI: LOCKED (%s) sent to client", EncryptedStorage::getLockReason());
+        } else {
+            queueLockdownStatus(meshtastic_LockdownStatus_State_LOCKED, "needs_auth", 0, 0, 0);
+            LOG_INFO("PhoneAPI: LOCKED (needs_auth) sent to client");
+        }
+    }
+#endif
+
     // Allow subclasses to know we've entered steady-state so they can lower power consumption
     onConfigComplete();
 
@@ -1097,6 +1532,7 @@ bool PhoneAPI::available()
     case STATE_SEND_CONFIG:
     case STATE_SEND_MODULECONFIG:
     case STATE_SEND_METADATA:
+    case STATE_SEND_REGION_PRESETS:
     case STATE_SEND_OWN_NODEINFO:
     case STATE_SEND_FILEMANIFEST:
     case STATE_SEND_COMPLETE_ID:
@@ -1121,6 +1557,10 @@ bool PhoneAPI::available()
         if (!clientNotification)
             clientNotification = service->getClientNotificationForPhone();
         bool hasPacket = !!queueStatusPacketForPhone || !!mqttClientProxyMessageForPhone || !!clientNotification;
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+        if (hasPendingLockdownStatus())
+            hasPacket = true;
+#endif
         if (hasPacket)
             return true;
 
@@ -1192,6 +1632,46 @@ bool PhoneAPI::handleToRadioPacket(meshtastic_MeshPacket &p)
 {
     printPacket("PACKET FROM PHONE", &p);
 
+#if defined(MESHTASTIC_ENCRYPTED_STORAGE) && defined(MESHTASTIC_PHONEAPI_ACCESS_CONTROL)
+    // Local admin gating happens here, synchronously on the dispatching
+    // task. Two distinct cases:
+    //
+    //   (a) lockdown_auth: handled inline. Passphrase never enters the
+    //       routed MeshPacket queue, and authorize-this-connection
+    //       runs while `this` is still on the call stack.
+    //
+    //   (b) Any other admin payload from an unauthorized connection:
+    //       dropped here. The previous design relied on AdminModule
+    //       to apply isLocalAdminAuthorized() during dispatch, but
+    //       AdminModule runs on the Router task — by then the
+    //       PhoneAPI dispatching task has already exited and the
+    //       per-connection auth context is unrecoverable. Putting
+    //       the gate here closes that race and covers H6/H7 from the
+    //       audit: get_config_request and set_config from unauthed
+    //       clients no longer reach AdminModule at all.
+    if (p.from == 0 && p.which_payload_variant == meshtastic_MeshPacket_decoded_tag &&
+        p.decoded.portnum == meshtastic_PortNum_ADMIN_APP) {
+        meshtastic_AdminMessage admin = meshtastic_AdminMessage_init_zero;
+        if (pb_decode_from_bytes(p.decoded.payload.bytes, p.decoded.payload.size, &meshtastic_AdminMessage_msg, &admin)) {
+            if (admin.which_payload_variant == meshtastic_AdminMessage_lockdown_auth_tag) {
+                handleLockdownAuthInline(admin.lockdown_auth);
+                // Wipe the decoded passphrase scratch — the byte array in
+                // p.decoded.payload.bytes is wiped by handleLockdownAuthInline.
+                volatile uint8_t *adminVol = const_cast<volatile uint8_t *>(admin.lockdown_auth.passphrase.bytes);
+                for (size_t i = 0; i < sizeof(admin.lockdown_auth.passphrase.bytes); i++)
+                    adminVol[i] = 0;
+                return true;
+            }
+            if (!getAdminAuthorized()) {
+                LOG_WARN("Lockdown: dropping admin payload variant=%d from unauthorized connection", admin.which_payload_variant);
+                return false;
+            }
+        }
+        // pb_decode failure: fall through to normal handling so the
+        // regular Router/AdminModule reject path can respond.
+    }
+#endif
+
 #if defined(ARCH_PORTDUINO)
     // For use with the simulator, we should not ignore duplicate packets from the phone
     if (SimRadio::instance == nullptr)
@@ -1260,3 +1740,314 @@ int PhoneAPI::onNotify(uint32_t newValue)
 
     return timeout ? -1 : 0; // If we timed out, MeshService should stop iterating through observers as we just removed one
 }
+
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+bool PhoneAPI::getAdminAuthorized() const
+{
+    // Runtime-toggle model: when lockdown is NOT active (a lockdown-capable
+    // build that hasn't been provisioned, or that was disabled), there is
+    // nothing to protect — every connection is implicitly authorized, so
+    // all the `if (!getAdminAuthorized())` redaction gates throughout
+    // getFromRadio() / handleToRadio() become no-ops and the device serves
+    // config exactly like stock firmware. Only once provisioned (lockdown
+    // active) do we consult the per-connection auth slot table.
+#ifdef MESHTASTIC_ENCRYPTED_STORAGE
+    if (!EncryptedStorage::isLockdownActive())
+        return true;
+#endif
+    concurrency::LockGuard g(&g_authSlotsMutex);
+    // const_cast is safe — findOrAllocSlot_LH only mutates the slot table,
+    // not the PhoneAPI itself, and the table key is just the pointer.
+    const auto *slot = findOrAllocSlot_LH(const_cast<PhoneAPI *>(this));
+    return slot && slot->authorized && slot->epoch == g_authEpoch;
+}
+
+void PhoneAPI::setAdminAuthorized(bool authorized)
+{
+    concurrency::LockGuard g(&g_authSlotsMutex);
+    auto *slot = findOrAllocSlot_LH(this);
+    if (!slot)
+        return; // slot table full — fail-closed
+    if (authorized) {
+        slot->epoch = g_authEpoch;
+        slot->authorized = true;
+    } else {
+        slot->authorized = false;
+        slot->epoch = 0;
+    }
+}
+
+void PhoneAPI::revokeAllAuth()
+{
+    {
+        concurrency::LockGuard g(&g_authSlotsMutex);
+        g_authEpoch++;
+    }
+    LOG_INFO("Lockdown: All connection auth revoked (Lock Now)");
+}
+
+void PhoneAPI::completePendingUnlocks(bool reloadOk)
+{
+    // Snapshot fields that we'll need outside the lock (we cannot call
+    // EncryptedStorage / setAdminAuthorized / unlockScreen while holding
+    // g_authSlotsMutex without risking re-entry — setAdminAuthorized
+    // itself takes the same lock).
+    constexpr size_t kMaxSnapshots = MAX_AUTH_SLOTS;
+    PhoneAPI *targets[kMaxSnapshots] = {};
+    size_t targetCount = 0;
+    {
+        concurrency::LockGuard guard(&g_authSlotsMutex);
+        for (auto &s : g_statusSlots) {
+            if (!s.pendingUnlockAfterReload || !s.who)
+                continue;
+            if (targetCount < kMaxSnapshots)
+                targets[targetCount++] = s.who;
+            // Clear the pending flag either way — failure path must not
+            // leave it set so a subsequent successful reload retries
+            // against the wrong PhoneAPI.
+            s.pendingUnlockAfterReload = false;
+        }
+    }
+
+    if (reloadOk) {
+        uint8_t boots = EncryptedStorage::getBootsRemaining();
+        uint32_t until = EncryptedStorage::getValidUntilEpoch();
+        for (size_t i = 0; i < targetCount; i++) {
+            PhoneAPI *p = targets[i];
+            p->setAdminAuthorized(true);
+            p->queueLockdownStatus(meshtastic_LockdownStatus_State_UNLOCKED, "", boots, until, 0);
+        }
+        // Screen-lock latch is cleared once any client successfully
+        // unlocks — the operator has proven the passphrase. Matches the
+        // re-verify path's behavior.
+        if (targetCount > 0)
+            meshtastic_security::unlockScreen();
+        LOG_INFO("Lockdown: post-reload completion: authorized %u connection(s)", (unsigned)targetCount);
+    } else {
+        // Storage corrupt — emit LOCKED(storage_corrupt) to every slot
+        // that was awaiting the unlock. setAdminAuthorized is NOT called
+        // so the connection stays redacted and any set_config it sends
+        // is dropped at the existing unauth gates. Caller (main.cpp) has
+        // already lockNow'd storage and broadcast-revoked.
+        for (size_t i = 0; i < targetCount; i++) {
+            targets[i]->queueLockdownStatus(meshtastic_LockdownStatus_State_LOCKED, "storage_corrupt", 0, 0, 0);
+        }
+        LOG_ERROR("Lockdown: post-reload completion: storage corrupt, notified %u connection(s)", (unsigned)targetCount);
+    }
+}
+
+void PhoneAPI::queueLockdownStatus(meshtastic_LockdownStatus_State state, const char *lock_reason, uint8_t boots_remaining,
+                                   uint32_t valid_until_epoch, uint32_t backoff_seconds)
+{
+    {
+        concurrency::LockGuard guard(&g_authSlotsMutex);
+        auto *slot = findOrAllocStatusSlot_LH(this);
+        if (!slot)
+            return; // slot table exhausted — fail-closed, no status delivered
+        buildStatus_LH(slot->status, state, lock_reason, boots_remaining, valid_until_epoch, backoff_seconds);
+        slot->hasPending = true;
+    }
+    if (service)
+        service->nudgeFromNum();
+}
+
+void PhoneAPI::broadcastLockdownStatus(meshtastic_LockdownStatus_State state, const char *lock_reason, uint8_t boots_remaining,
+                                       uint32_t valid_until_epoch, uint32_t backoff_seconds)
+{
+    bool anyOverwritten = false;
+    {
+        concurrency::LockGuard guard(&g_authSlotsMutex);
+        for (auto &s : g_statusSlots) {
+            if (s.who) {
+                buildStatus_LH(s.status, state, lock_reason, boots_remaining, valid_until_epoch, backoff_seconds);
+                s.hasPending = true;
+                anyOverwritten = true;
+            }
+        }
+    }
+    // Service nudge is shared across connections; one nudge wakes every
+    // drainer. Skip if no connection currently has a slot.
+    if (anyOverwritten && service)
+        service->nudgeFromNum();
+}
+
+bool PhoneAPI::hasPendingLockdownStatus() const
+{
+    concurrency::LockGuard guard(&g_authSlotsMutex);
+    for (const auto &s : g_statusSlots) {
+        if (s.who == this && s.hasPending)
+            return true;
+    }
+    return false;
+}
+
+#ifdef MESHTASTIC_ENCRYPTED_STORAGE
+bool PhoneAPI::handleLockdownAuthInline(const meshtastic_LockdownAuth &la)
+{
+    // Wipe passphrase bytes in the caller's decoded scratch on every exit.
+    auto zeroPassphrase = [&]() {
+        volatile uint8_t *ppVol = const_cast<volatile uint8_t *>(la.passphrase.bytes);
+        for (pb_size_t zi = 0; zi < la.passphrase.size; zi++)
+            ppVol[zi] = 0;
+    };
+
+    // Lock Now — only honored from a connection that has already proven
+    // the passphrase. Unauthenticated clients used to be able to trigger
+    // a reboot, which was a trivial local-presence DoS (any BLE/USB
+    // attacker could brick-loop the device). Now lock_now requires
+    // prior auth on this connection.
+    if (la.lock_now) {
+        if (!getAdminAuthorized()) {
+            LOG_WARN("Lockdown: LOCK NOW from unauthorized connection — denied");
+            queueLockdownStatus(meshtastic_LockdownStatus_State_UNLOCK_FAILED, "", 0, 0, 0);
+            zeroPassphrase();
+            return true;
+        }
+        LOG_INFO("Lockdown: LOCK NOW command received from authorized connection");
+        EncryptedStorage::lockNow();
+        revokeAllAuth();
+        queueLockdownStatus(meshtastic_LockdownStatus_State_LOCKED, "", 0, 0, 0);
+        zeroPassphrase();
+        rebootAtMsec = millis() + DEFAULT_REBOOT_SECONDS * 1000;
+        return true;
+    }
+
+    // Disable lockdown entirely. Requires the passphrase (must prove
+    // ownership before reverting at-rest encryption). We verify it here to
+    // load the DEK, then hand the heavy decrypt-revert work to the main
+    // loop via lockdownDisablePending — exactly like the unlock reload
+    // path, because decrypting + rewriting nodes.proto is too heavy for
+    // this transport-callback stack. APPROTECT is NOT reversed.
+    if (la.disable) {
+        if (la.passphrase.size < 1) {
+            LOG_WARN("Lockdown: disable with empty passphrase — rejecting");
+            queueLockdownStatus(meshtastic_LockdownStatus_State_UNLOCK_FAILED, "", 0, 0, 0);
+            zeroPassphrase();
+            return true;
+        }
+        if (!EncryptedStorage::isLockdownActive()) {
+            // Already off — nothing to do; report DISABLED so the client UI settles.
+            LOG_INFO("Lockdown: disable requested but lockdown is not active");
+            queueLockdownStatus(meshtastic_LockdownStatus_State_DISABLED, "", 0, 0, 0);
+            zeroPassphrase();
+            return true;
+        }
+        // Re-verify the passphrase (loads the DEK needed to decrypt files).
+        bool ok = EncryptedStorage::unlockWithPassphrase(la.passphrase.bytes, la.passphrase.size,
+                                                         EncryptedStorage::TOKEN_DEFAULT_BOOTS, 0, 0);
+        if (!ok) {
+            uint32_t backoff = EncryptedStorage::getBackoffSecondsRemaining();
+            queueLockdownStatus(meshtastic_LockdownStatus_State_UNLOCK_FAILED, "", 0, 0, backoff);
+            LOG_WARN("Lockdown: disable passphrase verification failed");
+            zeroPassphrase();
+            return true;
+        }
+        setAdminAuthorized(true);
+        lockdownDisablePending = true; // main loop runs nodeDB->disableLockdownToPlaintext() then reboots
+        LOG_INFO("Lockdown: disable authorized, deferring decrypt-revert to main loop");
+        zeroPassphrase();
+        return true;
+    }
+
+    // Empty-passphrase auth was previously a silent success — clients
+    // got no feedback and the device looked the same as it would after
+    // an actual no-op. Emit UNLOCK_FAILED with no backoff so honest
+    // clients can detect their own bug and an attacker still learns
+    // nothing they wouldn't from any other failed attempt.
+    if (la.passphrase.size < 1) {
+        LOG_WARN("Lockdown: lockdown_auth with empty passphrase and lock_now=false — rejecting");
+        queueLockdownStatus(meshtastic_LockdownStatus_State_UNLOCK_FAILED, "", 0, 0, 0);
+        zeroPassphrase();
+        return true;
+    }
+
+    // boots_remaining is uint32 on the wire but the token field is uint8.
+    // Silently truncating (256 -> 0 -> default 50) hides a real client
+    // bug. Reject explicitly so the client can correct its request.
+    if (la.boots_remaining > 255) {
+        LOG_WARN("Lockdown: boots_remaining=%u exceeds uint8 cap, rejecting", la.boots_remaining);
+        queueLockdownStatus(meshtastic_LockdownStatus_State_UNLOCK_FAILED, "", 0, 0, 0);
+        zeroPassphrase();
+        return true;
+    }
+
+    uint8_t boots = la.boots_remaining != 0 ? (uint8_t)la.boots_remaining : EncryptedStorage::TOKEN_DEFAULT_BOOTS;
+    uint32_t validUntilEpoch = la.valid_until_epoch;
+    // Client-supplied session cap when present; otherwise the
+    // firmware-side default. 0 from the client means "use firmware
+    // default", consistent with the boots_remaining sentinel.
+    uint32_t sessionMaxSeconds =
+        la.max_session_seconds != 0 ? la.max_session_seconds : MESHTASTIC_LOCKDOWN_SESSION_DEFAULT_SECONDS;
+
+    bool ok = false;
+    bool needsReload = false;
+    if (!EncryptedStorage::isUnlocked()) {
+        if (!EncryptedStorage::isProvisioned()) {
+            LOG_INFO("Lockdown: first-time provisioning with passphrase");
+            ok = EncryptedStorage::provisionPassphrase(la.passphrase.bytes, la.passphrase.size, boots, validUntilEpoch,
+                                                       sessionMaxSeconds);
+        } else {
+            LOG_INFO("Lockdown: unlock with passphrase");
+            ok = EncryptedStorage::unlockWithPassphrase(la.passphrase.bytes, la.passphrase.size, boots, validUntilEpoch,
+                                                        sessionMaxSeconds);
+        }
+        if (ok) {
+            needsReload = true;
+            // Mark this slot for the main-loop completion handler. Don't
+            // authorize or emit UNLOCKED yet — `config` / `channelFile`
+            // / `nodeDatabase` still hold the locked-default placeholders
+            // installed by loadFromDisk()'s !isUnlocked() branch. If we
+            // flipped the connection to authorized here, the client could
+            // read those placeholders as if they were the operator's real
+            // settings, or set_config write a corrupted baseline that
+            // overwrites the real config when reloadFromDisk swaps them
+            // in. completePendingUnlocks() runs on the main thread after
+            // reloadFromDisk has populated the real values and the radio
+            // has been reconfigured.
+            {
+                concurrency::LockGuard guard(&g_authSlotsMutex);
+                if (auto *slot = findOrAllocStatusSlot_LH(this))
+                    slot->pendingUnlockAfterReload = true;
+            }
+            lockdownReloadPending = true;
+            LOG_INFO("Lockdown: storage unlocked, awaiting reload before client visibility");
+        }
+    } else {
+        LOG_INFO("Lockdown: passphrase re-verify for admin authorization");
+        ok = EncryptedStorage::unlockWithPassphrase(la.passphrase.bytes, la.passphrase.size, boots, validUntilEpoch,
+                                                    sessionMaxSeconds);
+        if (ok) {
+            // Storage was already unlocked — no reload needed. Authorize
+            // and surface UNLOCKED to the client immediately.
+            setAdminAuthorized(true);
+            LOG_INFO("Lockdown: passphrase verified, this connection authorized");
+        }
+    }
+
+    if (ok && !needsReload) {
+        // Re-verify path: storage was already unlocked. Clear the screen
+        // latch and emit UNLOCKED now. The cold-unlock path defers both
+        // of these to completePendingUnlocks() once reloadFromDisk finishes.
+        meshtastic_security::unlockScreen();
+        queueLockdownStatus(meshtastic_LockdownStatus_State_UNLOCKED, "", EncryptedStorage::getBootsRemaining(),
+                            EncryptedStorage::getValidUntilEpoch(), 0);
+    } else if (ok && needsReload) {
+        // Cold-unlock path: deliberately no status emission yet — the
+        // client keeps seeing LOCKED until completePendingUnlocks()
+        // runs after a successful reload.
+    } else {
+        uint32_t backoff = EncryptedStorage::getBackoffSecondsRemaining();
+        queueLockdownStatus(meshtastic_LockdownStatus_State_UNLOCK_FAILED, "", 0, 0, backoff);
+        // Don't log backoff seconds — the client receives it in the
+        // UNLOCK_FAILED status anyway, and in non-DEBUG_MUTE builds the
+        // numeric value would otherwise spill onto a USB-attached
+        // attacker's serial terminal alongside other diagnostic noise.
+        LOG_WARN("Lockdown: passphrase verification failed");
+        (void)backoff;
+    }
+
+    zeroPassphrase();
+    return true;
+}
+#endif // MESHTASTIC_ENCRYPTED_STORAGE
+#endif // MESHTASTIC_PHONEAPI_ACCESS_CONTROL

src/mesh/PhoneAPI.h

@@ -4,6 +4,7 @@
 #include "concurrency/Lock.h"
 #include "mesh-pb-constants.h"
 #include "meshtastic/portnums.pb.h"
+#include <atomic>
 #include <cstdint>
 #include <deque>
 #include <iterator>
@@ -45,6 +46,7 @@ class PhoneAPI
         STATE_SEND_MY_INFO, // send our my info record
         STATE_SEND_OWN_NODEINFO,
         STATE_SEND_METADATA,
+        STATE_SEND_REGION_PRESETS,  // Send the region->valid-preset map (one message)
         STATE_SEND_CHANNELS,        // Send all channels
         STATE_SEND_CONFIG,          // Replacement for the old Radioconfig
         STATE_SEND_MODULECONFIG,    // Send Module specific config
@@ -170,6 +172,49 @@ class PhoneAPI
     bool isConnected() { return state != STATE_SEND_NOTHING; }
     bool isSendingPackets() { return state == STATE_SEND_PACKETS; }
 
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+    /// Per-connection auth: tracked in a small file-scope slot table keyed
+    /// by PhoneAPI*. Adding state members directly to PhoneAPI broke
+    /// USB-CDC enumeration on current nRF52 framework — even one extra
+    /// per-instance uint32_t was enough. Keeping all state out-of-line
+    /// avoids the issue.
+    void setAdminAuthorized(bool authorized);
+    bool getAdminAuthorized() const;
+
+    /// Lock Now: O(1) invalidation of every connection's auth by advancing
+    /// the global epoch. Subsequent gate checks see slot.myEpoch != epoch
+    /// and treat the connection as unauthenticated.
+    static void revokeAllAuth();
+
+    /// Called from the main loop after NodeDB::reloadFromDisk() finishes.
+    /// On reloadOk=true: any connection marked pending-unlock-after-reload
+    /// is promoted to authorized and receives an UNLOCKED status; the
+    /// screen-lock latch clears. On reloadOk=false: those connections
+    /// receive a LOCKED(storage_corrupt) status and remain unauthorized
+    /// so they cannot drive set_config against the corrupt baseline.
+    static void completePendingUnlocks(bool reloadOk);
+
+    /// Queue a LockdownStatus FromRadio for THIS connection only. Each
+    /// PhoneAPI owns its own pending-status slot in a file-scope table
+    /// (file-scope because adding fields directly to PhoneAPI broke
+    /// USB-CDC enumeration on nRF52); a status produced here will not
+    /// be delivered to any other connection. `lock_reason` may be
+    /// nullptr / empty for non-LOCKED states.
+    void queueLockdownStatus(meshtastic_LockdownStatus_State state, const char *lock_reason, uint8_t boots_remaining,
+                             uint32_t valid_until_epoch, uint32_t backoff_seconds);
+
+    /// Queue the same LockdownStatus on every active connection's slot.
+    /// Use for events with no specific originating connection (session
+    /// expiry tick in main.cpp, broadcast revocations, etc.). Per-
+    /// connection callers should prefer the instance method above to
+    /// avoid leaking one client's auth state to another.
+    static void broadcastLockdownStatus(meshtastic_LockdownStatus_State state, const char *lock_reason, uint8_t boots_remaining,
+                                        uint32_t valid_until_epoch, uint32_t backoff_seconds);
+
+    /// True iff this connection has a pending lockdown_status drain.
+    bool hasPendingLockdownStatus() const;
+#endif
+
   protected:
     /// Our fromradio packet while it is being assembled
     meshtastic_FromRadio fromRadioScratch = {};
@@ -211,6 +256,20 @@ class PhoneAPI
 
     APIType api_type = TYPE_NONE;
 
+#ifdef MESHTASTIC_PHONEAPI_ACCESS_CONTROL
+    // No per-instance auth members — see method-level note. All state lives
+    // in a file-scope slot table in PhoneAPI.cpp keyed by `this` pointer.
+
+    // Pending LockdownStatus storage is NOT a class member — having a
+    // meshtastic_LockdownStatus (~50 bytes with the char[33] lock_reason)
+    // as a PhoneAPI member broke USB-CDC enumeration on the nRF52 Adafruit
+    // framework. The exact mechanism wasn't pinned down, but moving the
+    // storage to a file-scope static in PhoneAPI.cpp side-steps it cleanly.
+    // Trade-off: all PhoneAPI instances share one pending slot. Acceptable
+    // because only one transport delivers a lockdown command at a time in
+    // any realistic scenario.
+#endif
+
   private:
     void releasePhonePacket();
 
@@ -248,6 +307,16 @@ class PhoneAPI
      */
     bool handleToRadioPacket(meshtastic_MeshPacket &p);
 
+#if defined(MESHTASTIC_ENCRYPTED_STORAGE) && defined(MESHTASTIC_PHONEAPI_ACCESS_CONTROL)
+    /// Synchronously handle a lockdown_auth AdminMessage from the local
+    /// client. Runs inside handleToRadioPacket so the originating
+    /// connection is reachable via `this` — avoids the async context
+    /// loss that broke the previous AdminModule path. Always consumes the
+    /// packet (returns true): lockdown_auth is local-only and must not be
+    /// forwarded to the mesh router.
+    bool handleLockdownAuthInline(const meshtastic_LockdownAuth &la);
+#endif
+
     /// If the mesh service tells us fromNum has changed, tell the phone
     virtual int onNotify(uint32_t newValue) override;
 };

src/mesh/PositionPrecision.cpp

@@ -16,11 +16,23 @@ uint32_t getPositionPrecisionForChannel(const meshtastic_Channel &channel)
 
 uint32_t getPositionPrecisionForChannel(uint8_t channelIndex)
 {
-    return getPositionPrecisionForChannel(channels.getByIndex(channelIndex));
+    const meshtastic_Channel &ch = channels.getByIndex(channelIndex);
+    if (ch.role == meshtastic_Channel_Role_DISABLED)
+        return 0;
+    uint32_t precision = getPositionPrecisionForChannel(ch);
+
+    // Never send a precise position on a publicly-decryptable channel (key check is gated on > ceiling).
+    if (precision > MAX_POSITION_PRECISION_PUBLIC_KEY && channels.usesPublicKey(channelIndex)) {
+        precision = MAX_POSITION_PRECISION_PUBLIC_KEY;
+    }
+    return precision;
 }
 
-static int32_t truncateCoordinate(int32_t coordinate, uint32_t precision)
+int32_t truncateCoordinate(int32_t coordinate, uint32_t precision)
 {
+    if (precision == 0 || precision >= 32)
+        return coordinate;
+
     uint32_t coordinateBits = static_cast<uint32_t>(coordinate);
     uint32_t truncated = coordinateBits & (UINT32_MAX << (32 - precision));
 
@@ -30,6 +42,11 @@ static int32_t truncateCoordinate(int32_t coordinate, uint32_t precision)
     return static_cast<int32_t>(truncated);
 }
 
+int32_t truncateCoordinate(int32_t coordinate, uint8_t precision)
+{
+    return truncateCoordinate(coordinate, static_cast<uint32_t>(precision));
+}
+
 void applyPositionPrecision(meshtastic_Position &position, uint32_t precision)
 {
     if (precision == 0) {

src/mesh/PositionPrecision.h

@@ -4,8 +4,23 @@
 #include "meshtastic/mesh.pb.h"
 #include <stdint.h>
 
+// Max precision on a publicly-decryptable channel. CCPA "precise geolocation" = within a ~564m (1,850ft) radius.
+// Precision is bit-truncation of latitude_i/longitude_i: the latitude cell stays ~constant in meters worldwide
+// (~700m at 15 bits), while only the longitude cell varies — widest at the equator, narrowing toward the poles.
+// 15 also matches the MQTT map-report public precision ceiling.
+#define MAX_POSITION_PRECISION_PUBLIC_KEY 15
+
+// Configured precision as-is; does NOT apply the public-key clamp -- use the channelIndex overload for the on-wire value.
 uint32_t getPositionPrecisionForChannel(const meshtastic_Channel &channel);
+
+// Configured precision, clamped to MAX_POSITION_PRECISION_PUBLIC_KEY when the channel's effective key is publicly decryptable.
 uint32_t getPositionPrecisionForChannel(uint8_t channelIndex);
+
+// Truncate a single latitude_i/longitude_i to `precision` significant bits, centered in the
+// resulting grid cell (stable under GPS jitter). precision 0 or >=32 returns the value unchanged.
+// The return is the coordinate (int32_t); the uint8_t overload only narrows the precision arg.
+int32_t truncateCoordinate(int32_t coordinate, uint32_t precision);
+int32_t truncateCoordinate(int32_t coordinate, uint8_t precision);
 void applyPositionPrecision(meshtastic_Position &position, uint32_t precision);
 bool applyPositionPrecision(meshtastic_MeshPacket &packet, uint32_t precision);
 bool applyPositionPrecisionForChannel(meshtastic_MeshPacket &packet, uint8_t channelIndex);

src/mesh/RadioInterface.cpp

@@ -26,6 +26,7 @@
 
 #ifdef ARCH_PORTDUINO
 #include "platform/portduino/PortduinoGlue.h"
+#include "platform/portduino/SerialHal.h"
 #include "platform/portduino/SimRadio.h"
 #include "platform/portduino/USBHal.h"
 #endif
@@ -60,6 +61,10 @@ const RegionProfile PROFILE_LITE = {PRESETS_LITE, 0.4, 0.0375f, false, false, 0,
 const RegionProfile PROFILE_NARROW = {PRESETS_NARROW, 0, 0.0104f, true, false, 0, 1, 1};
 // Ham '20kHz' profile. 15.6kHz bandwidth coerced to 20kHz via padding.
 const RegionProfile PROFILE_HAM_20KHZ = {PRESETS_TINY, 0, 0.0022f, false, true, 0, 2, 2};
+// Ham '100kHz' profile. 62.5kHz bandwidth coerced to 100kHz via padding.
+const RegionProfile PROFILE_HAM_100KHZ = {PRESETS_NARROW, 0, 0.01875f, false, true, 0, 1, 1};
+
+Observable<uint32_t> RadioInterface::loraRxPacketObservable;
 
 #define RDEF(name, freq_start, freq_end, duty_cycle, power_limit, frequency_switching, wide_lora, profile_ptr, default_preset,   \
              override_slot)                                                                                                      \
@@ -83,20 +88,30 @@ const RegionInfo regions[] = {
      */
     RDEF(EU_433, 433.0f, 434.0f, 10, 10, false, false, PROFILE_STD, PRESET(LONG_FAST), 0),
     /*
-       https://www.thethingsnetwork.org/docs/lorawan/duty-cycle/
-       https://www.thethingsnetwork.org/docs/lorawan/regional-parameters/
-       https://www.legislation.gov.uk/uksi/1999/930/schedule/6/part/III/made/data.xht?view=snippet&wrap=true
+        https://www.thethingsnetwork.org/docs/lorawan/duty-cycle/
+        https://www.thethingsnetwork.org/docs/lorawan/regional-parameters/
+        https://www.legislation.gov.uk/uksi/1999/930/schedule/6/part/III/made/data.xht?view=snippet&wrap=true
 
-       audio_permitted = false per regulation
+        audio_permitted = false per regulation
 
-       Special Note:
-       The link above describes LoRaWAN's band plan, stating a power limit of 16 dBm. This is their own suggested specification,
-       we do not need to follow it. The European Union regulations clearly state that the power limit for this frequency range is
-       500 mW, or 27 dBm. It also states that we can use interference avoidance and spectrum access techniques (such as LBT +
-       AFA) to avoid a duty cycle. (Please refer to line P page 22 of this document.)
-       https://www.etsi.org/deliver/etsi_en/300200_300299/30022002/03.01.01_60/en_30022002v030101p.pdf
-     */
+        Special Note:
+        The link above describes LoRaWAN's band plan, stating a power limit of 16 dBm. This is their own suggested specification,
+        we do not need to follow it. The European Union regulations clearly state that the power limit for this frequency range is
+        500 mW, or 27 dBm. It also states that we can use interference avoidance and spectrum access techniques (such as LBT +
+        AFA) to avoid a duty cycle. (Please refer to line P page 22 of this document.)
+        https://www.etsi.org/deliver/etsi_en/300200_300299/30022002/03.01.01_60/en_30022002v030101p.pdf
+
+        EU 866MHz band (Band no. 46b of 2006/771/EC and subsequent amendments) for Non-specific short-range devices (SRD)
+        Gives 4 channels at 865.7/866.3/866.9/867.5 MHz, 400 kHz gap plus 37.5 kHz padding between channels, 27 dBm,
+        duty cycle 2.5% (mobile) or 10% (fixed) https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02006D0771(01)-20250123
+
+        EU 868MHz band: 3 channels at 869.410/869.4625/869.577 MHz
+        Channel centres at 869.442/869.525/869.608 MHz,
+        10.4 kHz padding on channels, 27 dBm, duty cycle 10%
+    */
     RDEF(EU_868, 869.4f, 869.65f, 10, 27, false, false, PROFILE_EU868, PRESET(LONG_FAST), 0),
+    RDEF(EU_866, 865.6f, 867.6f, 2.5, 27, false, false, PROFILE_LITE, PRESET(LITE_FAST), 0),
+    RDEF(EU_N_868, 869.4f, 869.65f, 10, 27, false, false, PROFILE_NARROW, PRESET(NARROW_SLOW), 1),
 
     /*
         https://lora-alliance.org/wp-content/uploads/2020/11/lorawan_regional_parameters_v1.0.3reva_0.pdf
@@ -259,25 +274,21 @@ const RegionInfo regions[] = {
     */
     RDEF(ITU3_2M, 144.0f, 148.0f, 100, 30, false, false, PROFILE_HAM_20KHZ, PRESET(TINY_FAST), 33),
 
+    /*
+        ITU Region 2 (Americas) amateur 1.25m '125cm' allocation: 220.000 - 225.000 MHz.
+        Typical admin rules (e.g. US FCC Part 97) allow well above 30 dBm for licensed operators.
+        Note: Some countries do not allocate 220-222 MHz (e.g. USA, Canada). Check local law!
+
+        Default slot: 37 (223.650 MHz)
+        https://www.arrl.org/band-plan
+    */
+    RDEF(ITU2_125CM, 220.0f, 225.0f, 100, 30, false, false, PROFILE_HAM_100KHZ, PRESET(NARROW_SLOW), 37),
+
     /*
        2.4 GHZ WLAN Band equivalent. Only for SX128x chips.
     */
     RDEF(LORA_24, 2400.0f, 2483.5f, 100, 10, false, true, PROFILE_STD, PRESET(LONG_FAST), 0),
 
-    /*
-        EU 866MHz band (Band no. 46b of 2006/771/EC and subsequent amendments) for Non-specific short-range devices (SRD)
-        Gives 4 channels at 865.7/866.3/866.9/867.5 MHz, 400 kHz gap plus 37.5 kHz padding between channels, 27 dBm,
-        duty cycle 2.5% (mobile) or 10% (fixed) https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02006D0771(01)-20250123
-    */
-    RDEF(EU_866, 865.6f, 867.6f, 2.5, 27, false, false, PROFILE_LITE, PRESET(LITE_FAST), 0),
-
-    /*
-        EU 868MHz band: 3 channels at 869.410/869.4625/869.577 MHz
-        Channel centres at 869.442/869.525/869.608 MHz,
-        10.4 kHz padding on channels, 27 dBm, duty cycle 10%
-    */
-    RDEF(EU_N_868, 869.4f, 869.65f, 10, 27, false, false, PROFILE_NARROW, PRESET(NARROW_SLOW), 1),
-
     /*
         This needs to be last. Same as US.
     */
@@ -342,6 +353,9 @@ std::unique_ptr<RadioInterface> initLoRa()
               portduino_config.lora_spi_dev.c_str());
     if (portduino_config.lora_spi_dev == "ch341") {
         RadioLibHAL = ch341Hal;
+    } else if (portduino_config.lora_spi_dev == "serial") {
+        RadioLibHAL = new SerialHal(portduino_config.lora_serial_device, portduino_config.lora_serial_baud,
+                                    (uint32_t)portduino_config.lora_serial_timeout_ms);
     } else {
         if (RadioLibHAL != nullptr) {
             delete RadioLibHAL;
@@ -595,6 +609,62 @@ const RegionInfo *getRegion(meshtastic_Config_LoRaConfig_RegionCode code)
     return r;
 }
 
+void getRegionPresetMap(meshtastic_LoRaRegionPresetMap &map)
+{
+    map = meshtastic_LoRaRegionPresetMap_init_zero;
+
+    const size_t maxGroups = sizeof(map.groups) / sizeof(map.groups[0]);
+    const size_t maxRegions = sizeof(map.region_groups) / sizeof(map.region_groups[0]);
+    const size_t maxPresets = sizeof(map.groups[0].presets) / sizeof(map.groups[0].presets[0]);
+
+    // Coalesce regions that share an identical preset list into one group. Two
+    // regions belong to the same group when they share the same RegionProfile
+    // (which owns the preset list + licensing) AND the same default preset.
+    // Keyed by profile pointer, not the preset-array pointer: PROFILE_NARROW and
+    // PROFILE_HAM_100KHZ share PRESETS_NARROW but differ in licensedOnly.
+    const RegionProfile *groupProfile[sizeof(map.groups) / sizeof(map.groups[0])] = {};
+
+    for (const RegionInfo *r = regions; r->code != meshtastic_Config_LoRaConfig_RegionCode_UNSET; r++) {
+        // No room left to map any further region; once full we can't add more, so
+        // log once and stop. An incomplete map means clients won't constrain the
+        // omitted regions, so this must be discoverable rather than silent.
+        if (map.region_groups_count >= maxRegions) {
+            LOG_ERROR("Region preset map full at %u regions; remaining regions omitted", (unsigned)maxRegions);
+            break;
+        }
+
+        // Find the group this region belongs to, or create it.
+        int gi = -1;
+        for (pb_size_t g = 0; g < map.groups_count; g++) {
+            if (groupProfile[g] == r->profile && map.groups[g].default_preset == r->getDefaultPreset()) {
+                gi = g;
+                break;
+            }
+        }
+        if (gi < 0) {
+            if (map.groups_count >= maxGroups) {
+                // Out of group slots (should not happen for the current table). The
+                // region can't be advertised; skip it but make the gap visible.
+                LOG_ERROR("Region preset map out of group slots (%u); region %d omitted", (unsigned)maxGroups, r->code);
+                continue;
+            }
+            gi = map.groups_count++;
+            groupProfile[gi] = r->profile;
+            meshtastic_LoRaPresetGroup &grp = map.groups[gi];
+            grp.default_preset = r->getDefaultPreset();
+            grp.licensed_only = r->profile->licensedOnly;
+            grp.presets_count = 0;
+            for (size_t i = 0; r->profile->presets[i] != MODEM_PRESET_END && grp.presets_count < maxPresets; i++)
+                grp.presets[grp.presets_count++] = r->profile->presets[i];
+        }
+
+        // Map this region to its group (capacity checked at the top of the loop).
+        meshtastic_LoRaRegionPresets &rg = map.region_groups[map.region_groups_count++];
+        rg.region = r->code;
+        rg.group_index = (uint8_t)gi;
+    }
+}
+
 /**
  * Get duty cycle for current region. EU_866: 10% for routers, 2.5% for mobile.
  */
@@ -845,53 +915,116 @@ uint32_t RadioInterface::getChannelNum()
 }
 
 /**
- * Send an error-level client notification. Safe to call when service is null (e.g. in tests).
+ * Send a client notification (error level unless specified). Safe to call when service is null (e.g. in tests).
  */
-static void sendErrorNotification(const char *msg)
+static void sendErrorNotification(const char *msg, meshtastic_LogRecord_Level level = meshtastic_LogRecord_Level_ERROR)
 {
     if (!service)
         return;
     meshtastic_ClientNotification *cn = clientNotificationPool.allocZeroed();
     if (!cn)
         return;
-    cn->level = meshtastic_LogRecord_Level_ERROR;
+    cn->level = level;
     snprintf(cn->message, sizeof(cn->message), "%s", msg);
     service->sendClientNotification(cn);
 }
 
+// The EU_868/EU_866/EU_N_868 trio own mutually exclusive preset lists. Selecting a preset
+// locked to a sibling means the user wants that sibling region, not the default preset.
+static const meshtastic_Config_LoRaConfig_RegionCode SWAPPABLE_EU_REGIONS[] = {
+    meshtastic_Config_LoRaConfig_RegionCode_EU_868,
+    meshtastic_Config_LoRaConfig_RegionCode_EU_866,
+    meshtastic_Config_LoRaConfig_RegionCode_EU_N_868,
+};
+
 /**
- * Checks if a region is valid for the current settings.
+ * If currentRegion is one of the swappable EU regions and preset belongs to a sibling in
+ * that trio, return the sibling region that owns the preset. Returns nullptr otherwise.
+ */
+const RegionInfo *RadioInterface::regionSwapForPreset(meshtastic_Config_LoRaConfig_RegionCode currentRegion,
+                                                      meshtastic_Config_LoRaConfig_ModemPreset preset)
+{
+    bool currentIsSwappable = false;
+    for (auto code : SWAPPABLE_EU_REGIONS) {
+        if (code == currentRegion)
+            currentIsSwappable = true;
+    }
+    if (!currentIsSwappable)
+        return nullptr;
+
+    for (auto code : SWAPPABLE_EU_REGIONS) {
+        if (code == currentRegion)
+            continue;
+        const RegionInfo *sibling = getRegion(code);
+        if (sibling->supportsPreset(preset))
+            return sibling;
+    }
+    return nullptr;
+}
+
+/**
+ * Checks if a region is valid for the current settings, with no side effects.
+ * Safe to call speculatively (e.g. from UI pickers). When errBuf is given, it
+ * receives the human-readable failure reason.
  * Returns false if not compatible.
  */
-bool RadioInterface::validateConfigRegion(const meshtastic_Config_LoRaConfig &loraConfig)
+bool RadioInterface::checkConfigRegion(const meshtastic_Config_LoRaConfig &loraConfig, char *errBuf, size_t errLen)
 {
     const RegionInfo *newRegion = getRegion(loraConfig.region);
 
     // Reject unrecognized region codes (getRegion returns UNSET sentinel for unknown codes)
     if (newRegion->code != loraConfig.region) {
-        char err_string[160];
-        snprintf(err_string, sizeof(err_string), "Region code %d is not recognized", loraConfig.region);
-        LOG_ERROR("%s", err_string);
-        RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_INVALID_RADIO_SETTING);
-        sendErrorNotification(err_string);
+        if (errBuf)
+            snprintf(errBuf, errLen, "Region code %d is not recognized", loraConfig.region);
         return false;
     }
 
     // If you are not licensed, you can't use ham regions.
     if (newRegion->profile->licensedOnly && !devicestate.owner.is_licensed) {
-        char err_string[160];
-        snprintf(err_string, sizeof(err_string), "Region %s requires licensed mode", newRegion->name);
-        LOG_ERROR("%s", err_string);
-        RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_INVALID_RADIO_SETTING);
-        sendErrorNotification(err_string);
+        if (errBuf)
+            snprintf(errBuf, errLen, "Region %s requires licensed mode", newRegion->name);
         return false;
     }
 
+    // Hardware compatibility: wide-LoRa (2.4 GHz) regions need a wide-capable radio, and
+    // sub-GHz regions need a radio that can tune below 2.4 GHz (SX128x cannot). UNSET is
+    // always allowed since it is the "no region" state.
+    if (newRegion->code != meshtastic_Config_LoRaConfig_RegionCode_UNSET && RadioLibInterface::instance) {
+        const char *unsupported = nullptr;
+        if (newRegion->wideLora && !RadioLibInterface::instance->wideLora()) {
+            unsupported = "2.4 GHz";
+        } else if (!newRegion->wideLora && !RadioLibInterface::instance->supportsSubGhz()) {
+            unsupported = "sub-GHz";
+        }
+        if (unsupported) {
+            if (errBuf)
+                snprintf(errBuf, errLen, "Region %s needs %s, which this radio does not support", newRegion->name, unsupported);
+            return false;
+        }
+    }
+
     return true;
 }
 
 /**
- * Internal helper: validate or clamp a LoRa config against its region.
+ * Checks if a region is valid for the current settings. On failure, logs at ERROR,
+ * records a critical error, and sends a client notification.
+ * Returns false if not compatible.
+ */
+bool RadioInterface::validateConfigRegion(const meshtastic_Config_LoRaConfig &loraConfig)
+{
+    char err_string[160];
+    if (checkConfigRegion(loraConfig, err_string, sizeof(err_string)))
+        return true;
+
+    LOG_ERROR("%s", err_string);
+    RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_INVALID_RADIO_SETTING);
+    sendErrorNotification(err_string);
+    return false;
+}
+
+/**
+ * Internal helper: check or clamp a LoRa config against its region.
  * When clamp==false, returns false on first error (pure validation).
  * When clamp==true, fixes invalid settings in-place and returns true.
  */
@@ -908,11 +1041,29 @@ bool RadioInterface::checkOrClampConfigLora(meshtastic_Config_LoRaConfig &loraCo
     if (loraConfig.use_preset) {
         check_bw = modemPresetToBwKHz(loraConfig.modem_preset, newRegion->wideLora);
 
-        bool preset_valid = false;
-        for (size_t i = 0; i < newRegion->getNumPresets(); i++) {
-            if (loraConfig.modem_preset == newRegion->getAvailablePresets()[i]) {
+        bool preset_valid = newRegion->supportsPreset(loraConfig.modem_preset);
+        if (!preset_valid) {
+            // A preset locked to a sibling of the swappable EU regions swaps the region instead
+            // of clamping the preset, as long as the previous region was itself one of the trio.
+            const RegionInfo *swapRegion = regionSwapForPreset(loraConfig.region, loraConfig.modem_preset);
+            if (swapRegion) {
+                if (!clamp) {
+                    // Validation must still fail so callers route into the clamp, but quietly:
+                    // the clamp will accept this config by swapping regions, so don't record a
+                    // critical error or alarm the user over a change that is about to succeed.
+                    LOG_INFO("Preset %s implies region swap %s to %s, deferring to clamp", presetName, newRegion->name,
+                             swapRegion->name);
+                    return false;
+                }
+                snprintf(err_string, sizeof(err_string), "Preset %s swaps region %s to %s", presetName, newRegion->name,
+                         swapRegion->name);
+                LOG_INFO("%s", err_string);
+                sendErrorNotification(err_string, meshtastic_LogRecord_Level_INFO);
+
+                loraConfig.region = swapRegion->code;
+                newRegion = swapRegion;
+                check_bw = modemPresetToBwKHz(loraConfig.modem_preset, newRegion->wideLora);
                 preset_valid = true;
-                break;
             }
         }
         if (!preset_valid) {
@@ -1276,4 +1427,4 @@ size_t RadioInterface::beginSending(meshtastic_MeshPacket *p)
 
     sendingPacket = p;
     return p->encrypted.size + sizeof(PacketHeader);
-}
+}

src/mesh/RadioInterface.h

@@ -128,6 +128,9 @@ class RadioInterface
 
     virtual ~RadioInterface() {}
 
+    /// Fires once per valid received LoRa packet (arg = sender NodeNum). Used e.g. to flash LED_LORA.
+    static Observable<uint32_t> loraRxPacketObservable;
+
     /**
      * Coerce LoRa config fields (bandwidth/spread_factor) derived from presets.
      * This is used during early bootstrapping so UIs that display these fields directly remain consistent.
@@ -143,6 +146,10 @@ class RadioInterface
 
     virtual bool wideLora() { return false; }
 
+    /// Whether the radio can tune sub-GHz bands. False for 2.4 GHz-only chips (SX128x);
+    /// multiband chips like the LR1121 keep the default.
+    virtual bool supportsSubGhz() { return true; }
+
     /// Prepare hardware for sleep.  Call this _only_ for deep sleep, not needed for light sleep.
     virtual bool sleep() { return true; }
 
@@ -244,7 +251,12 @@ class RadioInterface
 
     static bool checkOrClampConfigLora(meshtastic_Config_LoRaConfig &loraConfig, bool clamp);
 
-    // Check if a candidate region is compatible and valid.
+    // Check if a candidate region is compatible and valid, with no side effects (safe for
+    // speculative UI checks). errBuf, if given, receives the failure reason.
+    static bool checkConfigRegion(const meshtastic_Config_LoRaConfig &loraConfig, char *errBuf = nullptr, size_t errLen = 0);
+
+    // Check if a candidate region is compatible and valid. On failure, logs at ERROR,
+    // records a critical error, and sends a client notification.
     static bool validateConfigRegion(const meshtastic_Config_LoRaConfig &loraConfig);
 
     // Check if a candidate radio configuration is valid.
@@ -253,6 +265,11 @@ class RadioInterface
     // Make a candidate radio configuration valid, even if it isn't.
     static void clampConfigLora(meshtastic_Config_LoRaConfig &loraConfig);
 
+    // If preset is locked to a sibling of currentRegion among the swappable EU regions
+    // (EU_868/EU_866/EU_N_868), return the sibling region owning the preset, else nullptr.
+    static const RegionInfo *regionSwapForPreset(meshtastic_Config_LoRaConfig_RegionCode currentRegion,
+                                                 meshtastic_Config_LoRaConfig_ModemPreset preset);
+
   protected:
     int8_t power = 17; // Set by applyModemConfig()
 

src/mesh/RadioLibInterface.cpp

@@ -614,6 +614,10 @@ void RadioLibInterface::handleReceiveInterrupt()
 
             printPacket("Lora RX", mp);
 
+#ifdef LED_LORA
+            loraRxPacketObservable.notifyObservers(mp->from);
+#endif
+
             airTime->logAirtime(RX_LOG, rxMsec);
 
             deliverToReceiver(mp);

src/mesh/ReliableRouter.cpp

@@ -151,6 +151,10 @@ void ReliableRouter::sniffReceived(const meshtastic_MeshPacket *p, const meshtas
             LOG_DEBUG("Received a %s for 0x%x, stopping retransmissions", ackId ? "ACK" : "NAK", ackId);
             if (ackId) {
                 stopRetransmission(p->to, ackId);
+                // M3: an end-to-end ACK proves the directed route to the ACK's sender currently works,
+                // so clear its failure count and refresh freshness (keeps a good route pinned).
+                if (!isBroadcast(getFrom(p)))
+                    noteRouteSuccess(getFrom(p), millis());
             } else {
                 stopRetransmission(p->to, nakId);
             }

src/mesh/Router.cpp

@@ -100,51 +100,31 @@ bool Router::shouldDecrementHopLimit(const meshtastic_MeshPacket *p)
         return true;
     }
 
-#if HAS_TRAFFIC_MANAGEMENT
-    // When router_preserve_hops is enabled, preserve hops for decoded packets that are not
-    // position or telemetry (those have their own exhaust_hop controls).
-    if (moduleConfig.has_traffic_management && moduleConfig.traffic_management.enabled &&
-        moduleConfig.traffic_management.router_preserve_hops && p->which_payload_variant == meshtastic_MeshPacket_decoded_tag &&
-        p->decoded.portnum != meshtastic_PortNum_POSITION_APP && p->decoded.portnum != meshtastic_PortNum_TELEMETRY_APP) {
-        LOG_DEBUG("Router hop preserved: port=%d from=0x%08x (traffic_management)", p->decoded.portnum, getFrom(p));
-        if (trafficManagementModule) {
-            trafficManagementModule->recordRouterHopPreserved();
-        }
-        return false;
-    }
-#endif
+    // router_preserve_hops: not suitable right now — removed from config until
+    // the right heuristics for when to preserve vs. exhaust hops are established.
+    // #if HAS_TRAFFIC_MANAGEMENT
+    //     if (moduleConfig.has_traffic_management &&
+    //         moduleConfig.traffic_management.router_preserve_hops && ...) { ... }
+    // #endif
 
-    // For subsequent hops, check if previous relay is a favorite router
-    // Optimized search for favorite routers with matching last byte
-    // Check ordering optimized for IoT devices (cheapest checks first)
-    for (size_t i = 0; i < nodeDB->getNumMeshNodes(); i++) {
-        meshtastic_NodeInfoLite *node = nodeDB->getMeshNodeByIndex(i);
-        if (!node)
-            continue;
-
-        // Check 1: is_favorite (cheapest - single bit test)
-        if (!nodeInfoLiteIsFavorite(node))
-            continue;
-
-        // Check 2: has_user (cheap - single bit test)
-        if (!nodeInfoLiteHasUser(node))
-            continue;
-
-        // Check 3: role check (moderate cost - multiple comparisons)
-        if (!IS_ONE_OF(node->role, meshtastic_Config_DeviceConfig_Role_ROUTER, meshtastic_Config_DeviceConfig_Role_ROUTER_LATE,
-                       meshtastic_Config_DeviceConfig_Role_CLIENT_BASE)) {
-            continue;
-        }
-
-        // Check 4: last byte extraction and comparison (most expensive)
-        if (nodeDB->getLastByteOfNodeNum(node->num) == p->relay_node) {
-            // Found a favorite router match
-            LOG_DEBUG("Identified favorite relay router 0x%x from last byte 0x%x", node->num, p->relay_node);
+    // For subsequent hops, preserve hop_limit only when the previous relay is UNAMBIGUOUSLY a favorite
+    // router. The relay_node byte is just the last byte of a 32-bit node number, so on a dense mesh it
+    // collides; the old "first matching node wins" scan could preserve hops for the wrong node
+    // (non-deterministic, depends on NodeDB order). resolveLastByte() reports a collision instead, and
+    // we re-check the favorite/router predicate on the single resolved node. On ambiguity/none we
+    // decrement (the safe default).
+    NodeNum resolved = 0;
+    if (nodeDB->resolveUniqueLastByte(p->relay_node, /*requireDirectNeighbor=*/false, &resolved)) {
+        const meshtastic_NodeInfoLite *node = nodeDB->getMeshNode(resolved);
+        if (node && nodeInfoLiteIsFavorite(node) && nodeInfoLiteHasUser(node) &&
+            IS_ONE_OF(node->role, meshtastic_Config_DeviceConfig_Role_ROUTER, meshtastic_Config_DeviceConfig_Role_ROUTER_LATE,
+                      meshtastic_Config_DeviceConfig_Role_CLIENT_BASE)) {
+            LOG_DEBUG("Identified unique favorite relay router 0x%x from last byte 0x%x", resolved, p->relay_node);
             return false; // Don't decrement hop_limit
         }
     }
 
-    // No favorite router match found, decrement hop_limit
+    // No unambiguous favorite router match found, decrement hop_limit
     return true;
 }
 
@@ -485,14 +465,16 @@ DecodeState perhapsDecode(meshtastic_MeshPacket *p)
     bool decrypted = false;
     ChannelIndex chIndex = 0;
 #if !(MESHTASTIC_EXCLUDE_PKI)
-    // Attempt PKI decryption first
-    if (p->channel == 0 && isToUs(p) && p->to > 0 && !isBroadcast(p->to) && nodeDB->getMeshNode(p->from) != nullptr &&
-        nodeDB->getMeshNode(p->from)->public_key.size > 0 && nodeDB->getMeshNode(p->to) != nullptr &&
-        nodeDB->getMeshNode(p->to)->public_key.size > 0 && rawSize > MESHTASTIC_PKC_OVERHEAD) {
+    // Attempt PKI decryption first. The sender's key may come from the hot
+    // store or the warm tier (nodes evicted from the hot store keep their key
+    // there), so DMs from long-tail nodes still decrypt.
+    meshtastic_NodeInfoLite_public_key_t fromKey = {0, {0}};
+    if (p->channel == 0 && isToUs(p) && p->to > 0 && !isBroadcast(p->to) && nodeDB->copyPublicKey(p->from, fromKey) &&
+        nodeDB->getMeshNode(p->to) != nullptr && nodeDB->getMeshNode(p->to)->public_key.size > 0 &&
+        rawSize > MESHTASTIC_PKC_OVERHEAD) {
         LOG_DEBUG("Attempt PKI decryption");
 
-        if (crypto->decryptCurve25519(p->from, nodeDB->getMeshNode(p->from)->public_key, p->id, rawSize, p->encrypted.bytes,
-                                      bytes)) {
+        if (crypto->decryptCurve25519(p->from, fromKey, p->id, rawSize, p->encrypted.bytes, bytes)) {
             LOG_INFO("PKI Decryption worked!");
 
             meshtastic_Data decodedtmp;
@@ -503,7 +485,7 @@ DecodeState perhapsDecode(meshtastic_MeshPacket *p)
                 decrypted = true;
                 LOG_INFO("Packet decrypted using PKI!");
                 p->pki_encrypted = true;
-                memcpy(&p->public_key.bytes, nodeDB->getMeshNode(p->from)->public_key.bytes, 32);
+                memcpy(p->public_key.bytes, fromKey.bytes, 32);
                 p->public_key.size = 32;
                 p->decoded = decodedtmp;
                 p->which_payload_variant = meshtastic_MeshPacket_decoded_tag; // change type to decoded
@@ -559,6 +541,38 @@ DecodeState perhapsDecode(meshtastic_MeshPacket *p)
         if (p->decoded.has_bitfield)
             p->decoded.want_response |= p->decoded.bitfield & BITFIELD_WANT_RESPONSE_MASK;
 
+#if !(MESHTASTIC_EXCLUDE_PKI) && !(MESHTASTIC_EXCLUDE_XEDDSA)
+        if (p->decoded.xeddsa_signature.size == XEDDSA_SIGNATURE_SIZE) {
+            meshtastic_NodeInfoLite *node = nodeDB->getMeshNode(p->from);
+            if (node && node->public_key.size == 32) {
+                p->xeddsa_signed =
+                    crypto->xeddsa_verify(node->public_key.bytes, p->from, p->id, p->decoded.portnum, p->decoded.payload.bytes,
+                                          p->decoded.payload.size, p->decoded.xeddsa_signature.bytes);
+                if (p->xeddsa_signed) {
+                    // Mark this node as a signer so future unsigned packets from it are rejected
+                    nodeInfoLiteSetBit(node, NODEINFO_BITFIELD_HAS_XEDDSA_SIGNED_MASK, true);
+                    LOG_DEBUG("Verified XEdDSA signature from 0x%08x", p->from);
+                } else {
+                    LOG_WARN("XEdDSA signature verification failed from 0x%08x, dropping", p->from);
+                    return DecodeState::DECODE_FAILURE;
+                }
+            } else {
+                LOG_DEBUG("No public key for 0x%08x, cannot verify XEdDSA signature", p->from);
+            }
+        } else {
+            // Unsigned packet — only reject the class of packet a signing node always signs:
+            // an unencrypted broadcast small enough to also carry a signature (see perhapsEncode()).
+            // Unicast packets and oversized broadcasts are never signed, so they must not be
+            // hard-failed here even if this node has signed before.
+            const meshtastic_NodeInfoLite *node = nodeDB->getMeshNode(p->from);
+            if (node && nodeInfoLiteHasXeddsaSigned(node) && isBroadcast(p->to) &&
+                p->decoded.payload.size + XEDDSA_SIGNATURE_SIZE < meshtastic_Constants_DATA_PAYLOAD_LEN) {
+                LOG_WARN("Dropping unsigned broadcast from 0x%08x that previously signed", p->from);
+                return DecodeState::DECODE_FAILURE;
+            }
+        }
+#endif
+
         /* Not actually ever used.
         // Decompress if needed. jm
         if (p->decoded.portnum == meshtastic_PortNum_TEXT_MESSAGE_COMPRESSED_APP) {
@@ -629,6 +643,18 @@ meshtastic_Routing_Error perhapsEncode(meshtastic_MeshPacket *p)
             p->decoded.has_bitfield = true;
             p->decoded.bitfield |= (config.lora.config_ok_to_mqtt << BITFIELD_OK_TO_MQTT_SHIFT);
             p->decoded.bitfield |= (p->decoded.want_response << BITFIELD_WANT_RESPONSE_SHIFT);
+#if !(MESHTASTIC_EXCLUDE_PKI) && !(MESHTASTIC_EXCLUDE_XEDDSA)
+            // Sign broadcast packets if payload + signature fits within the max Data payload.
+            // The actual encoded size is checked after pb_encode (TOO_LARGE).
+            if (!p->pki_encrypted && isBroadcast(p->to) &&
+                p->decoded.payload.size + XEDDSA_SIGNATURE_SIZE < meshtastic_Constants_DATA_PAYLOAD_LEN) {
+                if (crypto->xeddsa_sign(p->from, p->id, p->decoded.portnum, p->decoded.payload.bytes, p->decoded.payload.size,
+                                        p->decoded.xeddsa_signature.bytes)) {
+                    p->decoded.xeddsa_signature.size = XEDDSA_SIGNATURE_SIZE;
+                    LOG_DEBUG("XEdDSA signed packet 0x%08x", p->id);
+                }
+            }
+#endif
         }
 
         size_t numbytes = pb_encode_to_bytes(bytes, sizeof(bytes), &meshtastic_Data_msg, &p->decoded);
@@ -676,7 +702,10 @@ meshtastic_Routing_Error perhapsEncode(meshtastic_MeshPacket *p)
         ChannelIndex chIndex = p->channel; // keep as a local because we are about to change it
 
 #if !(MESHTASTIC_EXCLUDE_PKI)
-        meshtastic_NodeInfoLite *node = nodeDB->getMeshNode(p->to);
+        // Destination key from the hot store or the warm tier (evicted
+        // long-tail nodes keep their key there)
+        meshtastic_NodeInfoLite_public_key_t destKey = {0, {0}};
+        bool haveDestKey = nodeDB->copyPublicKey(p->to, destKey);
         // We may want to retool things so we can send a PKC packet when the client specifies a key and nodenum, even if the node
         // is not in the local nodedb
         // First, only PKC encrypt packets we are originating
@@ -699,18 +728,17 @@ meshtastic_Routing_Error perhapsEncode(meshtastic_MeshPacket *p)
             if (numbytes + MESHTASTIC_HEADER_LENGTH + MESHTASTIC_PKC_OVERHEAD > MAX_LORA_PAYLOAD_LEN)
                 return meshtastic_Routing_Error_TOO_LARGE;
             // Check for a known public key for the destination
-            if (node == nullptr || node->public_key.size != 32) {
+            if (!haveDestKey) {
                 LOG_WARN("Unknown public key for destination node 0x%08x (portnum %d), refusing to send legacy DM", p->to,
                          p->decoded.portnum);
                 return meshtastic_Routing_Error_PKI_SEND_FAIL_PUBLIC_KEY;
             }
-            if (p->pki_encrypted && !memfll(p->public_key.bytes, 0, 32) &&
-                memcmp(p->public_key.bytes, node->public_key.bytes, 32) != 0) {
+            if (p->pki_encrypted && !memfll(p->public_key.bytes, 0, 32) && memcmp(p->public_key.bytes, destKey.bytes, 32) != 0) {
                 LOG_WARN("Client public key differs from requested: 0x%02x, stored key begins 0x%02x", *p->public_key.bytes,
-                         *node->public_key.bytes);
+                         *destKey.bytes);
                 return meshtastic_Routing_Error_PKI_FAILED;
             }
-            crypto->encryptCurve25519(p->to, getFrom(p), node->public_key, p->id, numbytes, bytes, p->encrypted.bytes);
+            crypto->encryptCurve25519(p->to, getFrom(p), destKey, p->id, numbytes, bytes, p->encrypted.bytes);
             numbytes += MESHTASTIC_PKC_OVERHEAD;
             p->channel = 0;
             p->pki_encrypted = true;

src/mesh/Router.h

@@ -35,6 +35,14 @@ class Router : protected concurrency::OSThread, protected PacketHistory
      */
     void addInterface(std::unique_ptr<RadioInterface> _iface) { iface = std::move(_iface); }
 
+    /**
+     * Borrowed (non-owning) access to the radio interface — used by NodeDB
+     * after a lockdown unlock so it can push the freshly-loaded config to
+     * the SX12xx via reconfigure(). Returns nullptr when no radio has been
+     * attached (e.g. ARCH_PORTDUINO simulator before SimRadio bind).
+     */
+    RadioInterface *getRadioIface() { return iface.get(); }
+
     /**
      * do idle processing
      * Mostly looking in our incoming rxPacket queue and calling handleReceived.

src/mesh/SX128xInterface.h

@@ -19,6 +19,9 @@ template <class T> class SX128xInterface : public RadioLibInterface
 
     virtual bool wideLora() override;
 
+    /// SX128x is a 2.4 GHz-only chip; it cannot tune sub-GHz regions
+    virtual bool supportsSubGhz() override { return false; }
+
     /// Apply any radio provisioning changes
     /// Make sure the Driver is properly configured before calling init().
     /// \return true if initialisation succeeded.

src/mesh/SerialHalDevice.cpp

@@ -0,0 +1,385 @@
+#include "mesh/SerialHalDevice.h"
+#include "NodeDB.h"
+#include "SPILock.h"
+#include "concurrency/Periodic.h"
+#include "configuration.h"
+#include "mesh/StreamAPI.h"
+#include "mesh/generated/meshtastic/config.pb.h"
+#include <Arduino.h>
+#include <SPI.h>
+#include <cstring>
+#include <stdint.h>
+
+#if defined(ARCH_ESP32)
+#if defined(HW_SPI1_DEVICE)
+extern SPIClass SPI1;
+#endif
+#endif
+
+namespace
+{
+constexpr uint32_t SERIAL_PI_RISING = 1;
+constexpr uint32_t SERIAL_PI_FALLING = 2;
+constexpr uint32_t SERIAL_PI_INPUT = 0;
+constexpr uint32_t SERIAL_PI_OUTPUT = 1;
+constexpr size_t MAX_INTERRUPT_SLOTS = 8;
+constexpr int32_t INTERRUPT_POLL_MS = 5;
+
+struct InterruptSlot {
+    bool used = false;
+    uint32_t pin = 0;
+    uint32_t mode = 0;
+    volatile bool pending = false;
+};
+
+concurrency::Lock interruptMutex;
+InterruptSlot interruptSlots[MAX_INTERRUPT_SLOTS];
+StreamAPI *interruptStreamApi = nullptr;
+concurrency::Periodic *interruptEmitter = nullptr;
+
+int findSlotByPinLocked(uint32_t pin)
+{
+    for (size_t i = 0; i < MAX_INTERRUPT_SLOTS; ++i) {
+        if (interruptSlots[i].used && interruptSlots[i].pin == pin) {
+            return (int)i;
+        }
+    }
+    return -1;
+}
+
+int allocateSlotLocked()
+{
+    for (size_t i = 0; i < MAX_INTERRUPT_SLOTS; ++i) {
+        if (!interruptSlots[i].used) {
+            return (int)i;
+        }
+    }
+    return -1;
+}
+
+#if defined(ARCH_PORTDUINO) || defined(ARCH_RP2040)
+PinStatus toInterruptMode(uint32_t serialMode)
+{
+    if (serialMode == SERIAL_PI_RISING) {
+        return PinStatus::RISING;
+    }
+    if (serialMode == SERIAL_PI_FALLING) {
+        return PinStatus::FALLING;
+    }
+    return PinStatus::CHANGE;
+}
+#else
+int toInterruptMode(uint32_t serialMode)
+{
+    if (serialMode == SERIAL_PI_RISING) {
+        return RISING;
+    }
+    if (serialMode == SERIAL_PI_FALLING) {
+        return FALLING;
+    }
+    return CHANGE;
+}
+#endif
+
+int32_t pumpInterruptEvents();
+
+void ensureInterruptEmitter()
+{
+    if (!interruptEmitter) {
+        interruptEmitter = new concurrency::Periodic("SerialHalIrqEmitter", pumpInterruptEvents);
+    }
+}
+
+void emitInterruptEvent(uint32_t pin, StreamAPI *streamApi)
+{
+    if (streamApi == nullptr) {
+        return;
+    }
+
+    meshtastic_SerialHalResponse event = meshtastic_SerialHalResponse_init_zero;
+    event.transaction_id = 0; // asynchronous interrupt notification
+    event.result = meshtastic_SerialHalResponse_Result_OK;
+    event.value = pin; // host-side SerialHal treats value as interrupt pin
+    SerialHalDevice::emitResponse(event, streamApi);
+}
+
+void markPendingBySlot(uint8_t slot)
+{
+    if (slot < MAX_INTERRUPT_SLOTS && interruptSlots[slot].used) {
+        interruptSlots[slot].pending = true;
+    }
+}
+
+void isr0()
+{
+    markPendingBySlot(0);
+}
+void isr1()
+{
+    markPendingBySlot(1);
+}
+void isr2()
+{
+    markPendingBySlot(2);
+}
+void isr3()
+{
+    markPendingBySlot(3);
+}
+void isr4()
+{
+    markPendingBySlot(4);
+}
+void isr5()
+{
+    markPendingBySlot(5);
+}
+void isr6()
+{
+    markPendingBySlot(6);
+}
+void isr7()
+{
+    markPendingBySlot(7);
+}
+
+void (*const isrTable[MAX_INTERRUPT_SLOTS])() = {isr0, isr1, isr2, isr3, isr4, isr5, isr6, isr7};
+
+int32_t pumpInterruptEvents()
+{
+    uint32_t toEmit[MAX_INTERRUPT_SLOTS] = {0};
+    size_t emitCount = 0;
+    StreamAPI *streamApi = nullptr;
+
+    {
+        concurrency::LockGuard lock(&interruptMutex);
+        streamApi = interruptStreamApi;
+        for (size_t i = 0; i < MAX_INTERRUPT_SLOTS; ++i) {
+            if (interruptSlots[i].used && interruptSlots[i].pending) {
+                interruptSlots[i].pending = false;
+                toEmit[emitCount++] = interruptSlots[i].pin;
+            }
+        }
+    }
+
+    for (size_t i = 0; i < emitCount; ++i) {
+        emitInterruptEvent(toEmit[i], streamApi);
+    }
+
+    return INTERRUPT_POLL_MS;
+}
+} // namespace
+
+// Helper to safely set response result
+static inline void setResponseError(meshtastic_SerialHalResponse &response, meshtastic_SerialHalResponse_Result result,
+                                    const char *error = nullptr)
+{
+    response.result = result;
+    if (error != nullptr) {
+        snprintf(response.error, sizeof(response.error), "%s", error);
+    }
+}
+
+void SerialHalDevice::handleCommand(const uint8_t *buf, size_t len, StreamAPI *streamApi)
+{
+    if (buf == nullptr || streamApi == nullptr) {
+        return;
+    }
+
+    // Validate role - SerialHal commands only handled when config.lora.serial_hal_only
+    if (!config.lora.serial_hal_only) {
+        meshtastic_SerialHalResponse response = meshtastic_SerialHalResponse_init_zero;
+        response.result = meshtastic_SerialHalResponse_Result_UNSUPPORTED;
+        snprintf(response.error, sizeof(response.error), "SerialHal not enabled for this role");
+        emitResponse(response, streamApi);
+        return;
+    }
+
+    // Decode the command
+    meshtastic_SerialHalCommand cmd = meshtastic_SerialHalCommand_init_zero;
+    if (!pb_decode_from_bytes(buf, len, &meshtastic_SerialHalCommand_msg, &cmd)) {
+        meshtastic_SerialHalResponse response = meshtastic_SerialHalResponse_init_zero;
+        response.result = meshtastic_SerialHalResponse_Result_BAD_REQUEST;
+        snprintf(response.error, sizeof(response.error), "Failed to decode SerialHalCommand");
+        emitResponse(response, streamApi);
+        return;
+    }
+
+    // Initialize response with matching transaction_id
+    meshtastic_SerialHalResponse response = meshtastic_SerialHalResponse_init_zero;
+    response.transaction_id = cmd.transaction_id;
+    response.result = meshtastic_SerialHalResponse_Result_OK;
+
+    // Dispatch to operation handler
+    switch (cmd.type) {
+    case meshtastic_SerialHalCommand_Type_PIN_MODE:
+        handlePinMode(cmd, response);
+        break;
+    case meshtastic_SerialHalCommand_Type_DIGITAL_WRITE:
+        handleDigitalWrite(cmd, response);
+        break;
+    case meshtastic_SerialHalCommand_Type_DIGITAL_READ:
+        handleDigitalRead(cmd, response);
+        break;
+    case meshtastic_SerialHalCommand_Type_ATTACH_INTERRUPT:
+        handleAttachInterrupt(cmd, response);
+        break;
+    case meshtastic_SerialHalCommand_Type_DETACH_INTERRUPT:
+        handleDetachInterrupt(cmd, response);
+        break;
+    case meshtastic_SerialHalCommand_Type_SPI_TRANSFER:
+        handleSpiTransfer(cmd, response);
+        break;
+    case meshtastic_SerialHalCommand_Type_NOOP:
+        // NOOP: just return OK
+        break;
+    default:
+        response.result = meshtastic_SerialHalResponse_Result_UNSUPPORTED;
+        snprintf(response.error, sizeof(response.error), "Unknown SerialHal operation type");
+        break;
+    }
+
+    emitResponse(response, streamApi);
+}
+
+void SerialHalDevice::handlePinMode(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response)
+{
+    // LOG_DEBUG("SerialHalDevice: pinMode pin=%u mode=%u", cmd.pin, cmd.mode);
+    if (cmd.mode == SERIAL_PI_INPUT) {
+        pinMode((int)cmd.pin, INPUT);
+    } else if (cmd.mode == SERIAL_PI_OUTPUT) {
+        pinMode((int)cmd.pin, OUTPUT);
+    } else {
+        setResponseError(response, meshtastic_SerialHalResponse_Result_BAD_REQUEST, "Unsupported pin mode");
+    }
+}
+
+void SerialHalDevice::handleDigitalWrite(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response)
+{
+    // LOG_DEBUG("SerialHalDevice: digitalWrite pin=%u value=%u", cmd.pin, cmd.value);
+    digitalWrite((int)cmd.pin, cmd.value ? HIGH : LOW);
+}
+
+void SerialHalDevice::handleDigitalRead(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response)
+{
+    // LOG_DEBUG("SerialHalDevice: digitalRead pin=%u", cmd.pin);
+    response.value = (uint32_t)digitalRead((int)cmd.pin);
+}
+
+void SerialHalDevice::handleAttachInterrupt(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response)
+{
+    // LOG_DEBUG("SerialHalDevice: attachInterrupt pin=%u mode=%u", cmd.pin, cmd.mode);
+
+    ensureInterruptEmitter();
+
+    int slot = -1;
+    {
+        concurrency::LockGuard lock(&interruptMutex);
+        slot = findSlotByPinLocked(cmd.pin);
+        if (slot < 0) {
+            slot = allocateSlotLocked();
+        }
+
+        if (slot >= 0) {
+            interruptSlots[slot].used = true;
+            interruptSlots[slot].pin = cmd.pin;
+            interruptSlots[slot].mode = cmd.mode;
+            interruptSlots[slot].pending = false;
+        }
+    }
+
+    if (slot < 0) {
+        setResponseError(response, meshtastic_SerialHalResponse_Result_ERROR, "No interrupt slots available");
+        return;
+    }
+
+    ::attachInterrupt((int)cmd.pin, isrTable[slot], toInterruptMode(cmd.mode));
+}
+
+void SerialHalDevice::handleDetachInterrupt(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response)
+{
+    // LOG_DEBUG("SerialHalDevice: detachInterrupt pin=%u", cmd.pin);
+
+    ::detachInterrupt((int)cmd.pin);
+
+    {
+        concurrency::LockGuard lock(&interruptMutex);
+        const int slot = findSlotByPinLocked(cmd.pin);
+        if (slot >= 0) {
+            interruptSlots[slot] = InterruptSlot{};
+        }
+    }
+}
+
+void SerialHalDevice::handleSpiTransfer(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response)
+{
+    if (cmd.data.size == 0) {
+        return;
+    }
+
+#if !ARCH_PORTDUINO
+    if (spiLock == nullptr) {
+        setResponseError(response, meshtastic_SerialHalResponse_Result_ERROR, "SPI lock not initialized");
+        return;
+    }
+
+#if defined(HW_SPI1_DEVICE)
+    SPIClass &spiBus = SPI1;
+#else
+    SPIClass &spiBus = SPI;
+#endif
+
+    response.data.size = cmd.data.size;
+
+    {
+        concurrency::LockGuard guard(spiLock);
+        spiBus.beginTransaction(SPISettings(4000000, MSBFIRST, SPI_MODE0));
+#ifdef ARCH_ESP32
+        spiBus.transferBytes(cmd.data.bytes, response.data.bytes, cmd.data.size);
+#else
+        spiBus.transfer(cmd.data.bytes, response.data.bytes, cmd.data.size);
+#endif
+        spiBus.endTransaction();
+    }
+#else
+    // SPI wiring is board/radio-specific; keep this explicit for now.
+    response.result = meshtastic_SerialHalResponse_Result_UNSUPPORTED;
+    snprintf(response.error, sizeof(response.error), "SPI not supported on this platform");
+#endif
+}
+
+void SerialHalDevice::emitResponse(const meshtastic_SerialHalResponse &response, StreamAPI *streamApi)
+{
+    if (streamApi == nullptr) {
+        return;
+    }
+
+    // Encode the response
+    uint8_t encoded[meshtastic_SerialHalResponse_size] = {0};
+    const size_t responseLen =
+        pb_encode_to_bytes(encoded, sizeof(encoded), &meshtastic_SerialHalResponse_msg, static_cast<const void *>(&response));
+
+    if (responseLen == 0 || responseLen > 0xFFFF) {
+        LOG_ERROR("SerialHalDevice: Failed to encode response (len=%zu)", responseLen);
+        return;
+    }
+
+    // Build frame with StreamAPI framing: START1 SERIALHAL_MAGIC LEN_H LEN_L [payload]
+    constexpr uint8_t START1 = 0x94;
+    constexpr uint8_t SERIALHAL_MAGIC = 0xA5;
+
+    uint8_t hdr[4];
+    hdr[0] = START1;
+    hdr[1] = SERIALHAL_MAGIC;
+    hdr[2] = (uint8_t)((responseLen >> 8) & 0xFF); // LEN_H
+    hdr[3] = (uint8_t)(responseLen & 0xFF);        // LEN_L
+
+    // Emit via StreamAPI (this uses the internal txBuf + framing)
+    streamApi->emitSerialHalResponse(hdr, sizeof(hdr), encoded, responseLen);
+
+    // Keep a recent stream instance so async interrupt events can be emitted.
+    {
+        concurrency::LockGuard lock(&interruptMutex);
+        interruptStreamApi = streamApi;
+    }
+}

src/mesh/SerialHalDevice.h

@@ -0,0 +1,90 @@
+#pragma once
+
+#include "mesh/generated/meshtastic/serial_hal.pb.h"
+#include <cstdint>
+
+/**
+ * @brief Device-side handler for SerialHal GPIO/SPI operations over StreamAPI framing.
+ *
+ * This module decodes SerialHalCommand protobufs received from a host and executes
+ * the requested GPIO (pinMode, digitalWrite, digitalRead, attach/detachInterrupt) or
+ * SPI operations, then returns results via SerialHalResponse.
+ *
+ * Usage:
+ *  1. Override StreamAPI::handleSerialHalCommand() in a subclass
+ *  2. Call SerialHalDevice::handleCommand(buf, len, streamApi)
+ *  3. SerialHalDevice will decode, execute, and emit the response
+ *
+ * The handler is only active when config.lora.serial_hal_only is true.
+ */
+
+class StreamAPI; // forward declaration
+
+class SerialHalDevice
+{
+  public:
+    /**
+     * @brief Process a SerialHalCommand and emit a response.
+     *
+     * Decodes the protobuf, validates the operation, executes it on the device,
+     * and writes the response back via the StreamAPI instance.
+     *
+     * @param buf     Pointer to the encoded SerialHalCommand protobuf payload (not including framing)
+     * @param len     Length of the encoded payload
+     * @param streamApi Pointer to the StreamAPI instance (used for emitting responses)
+     */
+    static void handleCommand(const uint8_t *buf, size_t len, StreamAPI *streamApi);
+
+    /**
+     * @brief Emit a SerialHalResponse back to the host via StreamAPI framing.
+     *
+     * Encodes the response protobuf and sends it with proper framing (START1 SERIALHAL_MAGIC LEN_H LEN_L payload).
+     *
+     * @param response The response to send
+     * @param streamApi Pointer to the StreamAPI instance
+     */
+    static void emitResponse(const meshtastic_SerialHalResponse &response, StreamAPI *streamApi);
+
+  private:
+    /**
+     * @brief Execute a GPIO pinMode operation.
+     * @param cmd Decoded SerialHalCommand with PIN_MODE type
+     * @param response Response object to fill with result
+     */
+    static void handlePinMode(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response);
+
+    /**
+     * @brief Execute a GPIO digitalWrite operation.
+     * @param cmd Decoded SerialHalCommand with DIGITAL_WRITE type
+     * @param response Response object to fill with result
+     */
+    static void handleDigitalWrite(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response);
+
+    /**
+     * @brief Execute a GPIO digitalRead operation.
+     * @param cmd Decoded SerialHalCommand with DIGITAL_READ type
+     * @param response Response object to fill with result (value field contains read result)
+     */
+    static void handleDigitalRead(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response);
+
+    /**
+     * @brief Execute an attachInterrupt operation.
+     * @param cmd Decoded SerialHalCommand with ATTACH_INTERRUPT type
+     * @param response Response object to fill with result
+     */
+    static void handleAttachInterrupt(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response);
+
+    /**
+     * @brief Execute a detachInterrupt operation.
+     * @param cmd Decoded SerialHalCommand with DETACH_INTERRUPT type
+     * @param response Response object to fill with result
+     */
+    static void handleDetachInterrupt(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response);
+
+    /**
+     * @brief Execute an SPI transfer operation.
+     * @param cmd Decoded SerialHalCommand with SPI_TRANSFER type and data to send
+     * @param response Response object to fill with result (data field contains received bytes)
+     */
+    static void handleSpiTransfer(const meshtastic_SerialHalCommand &cmd, meshtastic_SerialHalResponse &response);
+};

src/mesh/StreamAPI.cpp

@@ -1,12 +1,15 @@
 #include "StreamAPI.h"
 #include "PowerFSM.h"
 #include "RTC.h"
+#include "RedirectablePrint.h"
+#include "SerialHalDevice.h"
 #include "Throttle.h"
 #include "concurrency/LockGuard.h"
 #include "configuration.h"
 
 #define START1 0x94
 #define START2 0xc3
+#define SERIALHAL_MAGIC 0xa5 // second framing byte for SerialHal frames (START1 SH_MAGIC LEN_H LEN_L PAYLOAD)
 #define HEADER_LEN 4
 
 int32_t StreamAPI::runOncePart()
@@ -79,18 +82,29 @@ int32_t StreamAPI::handleRecStream(const char *buf, uint16_t bufLen)
         if (ptr == 0) { // looking for START1
             if (c != START1)
                 rxPtr = 0;     // failed to find framing
-        } else if (ptr == 1) { // looking for START2
-            if (c != START2)
-                rxPtr = 0;                             // failed to find framing
+        } else if (ptr == 1) { // discriminate frame type on second byte
+            if (c == START2) {
+                rxIsSerialHal = false; // standard ToRadio frame
+                serialHalRxActive.store(false);
+                RedirectablePrint::setSerialHalLogSuppressed(false);
+            } else if (c == SERIALHAL_MAGIC) {
+                rxIsSerialHal = true; // SerialHal command frame
+                serialHalRxActive.store(true);
+                RedirectablePrint::setSerialHalLogSuppressed(true);
+            } else {
+                rxPtr = 0; // unrecognised second byte — not our frame
+                serialHalRxActive.store(false);
+                RedirectablePrint::setSerialHalLogSuppressed(false);
+            }
         } else if (ptr >= HEADER_LEN - 1) {            // we have at least read our 4 byte framing
             uint32_t len = (rxBuf[2] << 8) + rxBuf[3]; // big endian 16 bit length follows framing
 
             // console->printf("len %d\n", len);
 
             if (ptr == HEADER_LEN - 1) {
-                // we _just_ finished our 4 byte header, validate length now (note: a length of zero is a valid
-                // protobuf also)
-                if (len > MAX_TO_FROM_RADIO_SIZE)
+                // we _just_ finished our 4 byte header, validate length now
+                uint32_t maxLen = rxIsSerialHal ? (uint32_t)meshtastic_SerialHalCommand_size : MAX_TO_FROM_RADIO_SIZE;
+                if (len > maxLen)
                     rxPtr = 0; // length is bogus, restart search for framing
             }
 
@@ -98,8 +112,16 @@ int32_t StreamAPI::handleRecStream(const char *buf, uint16_t bufLen)
                 if (ptr + 1 >= len + HEADER_LEN) { // have we received all of the payload?
                     rxPtr = 0;                     // start over again on the next packet
 
-                    // If we didn't just fail the packet and we now have the right # of bytes, parse it
-                    handleToRadio(rxBuf + HEADER_LEN, len);
+                    // Dispatch based on which frame type we identified at byte 1
+                    if (rxIsSerialHal)
+                        handleSerialHalCommand(rxBuf + HEADER_LEN, len);
+                    else
+                        handleToRadio(rxBuf + HEADER_LEN, len);
+
+                    if (rxIsSerialHal)
+                        serialHalRxActive.store(false);
+                    if (rxIsSerialHal)
+                        RedirectablePrint::setSerialHalLogSuppressed(false);
                 }
         }
     }
@@ -114,7 +136,12 @@ int32_t StreamAPI::readStream()
     if (!stream->available()) {
         // Nothing available this time, if the computer has talked to us recently, poll often, otherwise let CPU sleep a long time
         bool recentRx = Throttle::isWithinTimespanMs(lastRxMsec, 2000);
-        return recentRx ? 5 : 250;
+        if (!recentRx)
+            return 250; // Sleep a long time if we haven't heard from the computer in a while
+        if (serialHalRxActive.load())
+            return 0; // If we are in the middle of a SerialHal transaction, don't sleep at all because we want to be as
+                      // responsive as possible to incoming SerialHal bytes
+        return 5;     // Otherwise, poll frequently for new data
     } else {
         while (stream->available()) { // Currently we never want to block
             int cInt = stream->read();
@@ -135,18 +162,30 @@ int32_t StreamAPI::readStream()
             if (ptr == 0) { // looking for START1
                 if (c != START1)
                     rxPtr = 0;     // failed to find framing
-            } else if (ptr == 1) { // looking for START2
-                if (c != START2)
-                    rxPtr = 0;                             // failed to find framing
+            } else if (ptr == 1) { // discriminate frame type on second byte
+                if (c == START2) {
+                    rxIsSerialHal = false; // standard ToRadio frame
+                    serialHalRxActive.store(false);
+                    RedirectablePrint::setSerialHalLogSuppressed(false);
+                } else if (c == SERIALHAL_MAGIC) {
+                    rxIsSerialHal = true; // SerialHal command frame
+                    serialHalRxActive.store(true);
+                    RedirectablePrint::setSerialHalLogSuppressed(true);
+                    LOG_WARN("StreamAPI: Detected SerialHal command frame");
+                } else {
+                    rxPtr = 0; // unrecognised second byte — not our frame
+                    serialHalRxActive.store(false);
+                    RedirectablePrint::setSerialHalLogSuppressed(false);
+                }
             } else if (ptr >= HEADER_LEN - 1) {            // we have at least read our 4 byte framing
                 uint32_t len = (rxBuf[2] << 8) + rxBuf[3]; // big endian 16 bit length follows framing
 
                 // console->printf("len %d\n", len);
 
                 if (ptr == HEADER_LEN - 1) {
-                    // we _just_ finished our 4 byte header, validate length now (note: a length of zero is a valid
-                    // protobuf also)
-                    if (len > MAX_TO_FROM_RADIO_SIZE)
+                    // we _just_ finished our 4 byte header, validate length now
+                    uint32_t maxLen = rxIsSerialHal ? (uint32_t)meshtastic_SerialHalCommand_size : MAX_TO_FROM_RADIO_SIZE;
+                    if (len > maxLen)
                         rxPtr = 0; // length is bogus, restart search for framing
                 }
 
@@ -154,8 +193,16 @@ int32_t StreamAPI::readStream()
                     if (ptr + 1 >= len + HEADER_LEN) { // have we received all of the payload?
                         rxPtr = 0;                     // start over again on the next packet
 
-                        // If we didn't just fail the packet and we now have the right # of bytes, parse it
-                        handleToRadio(rxBuf + HEADER_LEN, len);
+                        // Dispatch based on which frame type we identified at byte 1
+                        if (rxIsSerialHal)
+                            handleSerialHalCommand(rxBuf + HEADER_LEN, len);
+                        else
+                            handleToRadio(rxBuf + HEADER_LEN, len);
+
+                        if (rxIsSerialHal)
+                            serialHalRxActive.store(false);
+                        if (rxIsSerialHal)
+                            RedirectablePrint::setSerialHalLogSuppressed(false);
                     }
             }
         }
@@ -199,6 +246,10 @@ void StreamAPI::emitRebooted()
 
 void StreamAPI::emitLogRecord(meshtastic_LogRecord_Level level, const char *src, const char *format, va_list arg)
 {
+    if (serialHalRxActive.load()) {
+        return;
+    }
+
     // IMPORTANT: do NOT touch `fromRadioScratch` or `txBuf` here — those
     // belong to the main packet-emission path and a LOG_ firing during
     // `writeStream()` would corrupt an in-flight encode. We keep a
@@ -249,4 +300,31 @@ void StreamAPI::onConnectionChanged(bool connected)
         // received a packet in a while
         powerFSM.trigger(EVENT_SERIAL_DISCONNECTED);
     }
+}
+
+void StreamAPI::handleSerialHalCommand(const uint8_t *buf, size_t len)
+{
+    // Default implementation: dispatch to SerialHalDevice for GPIO/SPI handling
+    SerialHalDevice::handleCommand(buf, len, this);
+}
+
+void StreamAPI::emitSerialHalResponse(const uint8_t *hdr, size_t hdrLen, const uint8_t *payload, size_t payloadLen)
+{
+    if (hdr == nullptr || hdrLen != 4 || payload == nullptr || payloadLen > meshtastic_SerialHalResponse_size) {
+        LOG_ERROR("StreamAPI: Invalid SerialHal response parameters");
+        return;
+    }
+
+    // Build complete frame in a temporary buffer
+    uint8_t frame[4 + meshtastic_SerialHalResponse_size];
+    memcpy(frame, hdr, hdrLen);
+    memcpy(frame + hdrLen, payload, payloadLen);
+
+    size_t totalLen = hdrLen + payloadLen;
+
+    // Serialize stream writes against other emit operations via streamLock
+    concurrency::LockGuard guard(&streamLock);
+    stream->write(frame, totalLen);
+    stream->flush();
+    LOG_WARN("StreamAPI: Emitted SerialHal response frame (len=%zu)", totalLen);
 }

src/mesh/StreamAPI.h

@@ -4,10 +4,15 @@
 #include "Stream.h"
 #include "concurrency/Lock.h"
 #include "concurrency/OSThread.h"
+#include "generated/meshtastic/serial_hal.pb.h"
+#include <atomic>
 #include <cstdarg>
 
-// A To/FromRadio packet + our 32 bit header
-#define MAX_STREAM_BUF_SIZE (MAX_TO_FROM_RADIO_SIZE + sizeof(uint32_t))
+// Buffer sized for the larger of a full ToRadio/FromRadio payload or a full SerialHalCommand payload, plus header.
+#define MAX_STREAM_PAYLOAD_SIZE                                                                                                  \
+    (MAX_TO_FROM_RADIO_SIZE > (int)meshtastic_SerialHalCommand_size ? MAX_TO_FROM_RADIO_SIZE                                     \
+                                                                    : (int)meshtastic_SerialHalCommand_size)
+#define MAX_STREAM_BUF_SIZE (MAX_STREAM_PAYLOAD_SIZE + (int)sizeof(uint32_t))
 
 /**
  * A version of our 'phone' API that talks over a Stream.  So therefore well suited to use with serial links
@@ -39,6 +44,8 @@ class StreamAPI : public PhoneAPI
 
     uint8_t rxBuf[MAX_STREAM_BUF_SIZE] = {0};
     size_t rxPtr = 0;
+    bool rxIsSerialHal = false; ///< true when the current in-progress frame is a SerialHal frame (START1 SH_MAGIC ...)
+    std::atomic<bool> serialHalRxActive{false};
 
     /// time of last rx, used, to slow down our polling if we haven't heard from anyone
     uint32_t lastRxMsec = 0;
@@ -56,6 +63,17 @@ class StreamAPI : public PhoneAPI
     /// Check the current underlying physical link to see if the client is currently connected
     virtual bool checkIsConnected() override = 0;
 
+    /**
+     * Emit a SerialHal response frame with proper framing (START1 SERIALHAL_MAGIC LEN_H LEN_L payload).
+     * Called by SerialHalDevice to send responses back to the host.
+     *
+     * @param hdr     4-byte header (START1 SERIALHAL_MAGIC LEN_H LEN_L)
+     * @param hdrLen  Length of header (should be 4)
+     * @param payload Encoded SerialHalResponse protobuf payload
+     * @param payloadLen Length of payload
+     */
+    void emitSerialHalResponse(const uint8_t *hdr, size_t hdrLen, const uint8_t *payload, size_t payloadLen);
+
   private:
     /**
      * Read any rx chars from the link and call handleToRadio
@@ -75,6 +93,12 @@ class StreamAPI : public PhoneAPI
      */
     void emitRebooted();
 
+    /**
+     * Called when a complete SerialHal-framed packet has been received.
+     * Default implementation dispatches to SerialHalDevice for GPIO/SPI handling.
+     */
+    virtual void handleSerialHalCommand(const uint8_t *buf, size_t len);
+
     virtual void onConnectionChanged(bool connected) override;
 
     /**

src/mesh/TypeConversions.cpp

@@ -18,6 +18,7 @@ meshtastic_NodeInfo TypeConversions::ConvertToNodeInfo(const meshtastic_NodeInfo
     info.is_ignored = nodeInfoLiteIsIgnored(lite);
     info.is_key_manually_verified = nodeInfoLiteIsKeyManuallyVerified(lite);
     info.is_muted = nodeInfoLiteIsMuted(lite);
+    info.has_xeddsa_signed = nodeInfoLiteHasXeddsaSigned(lite);
 
     if (lite->has_hops_away) {
         info.has_hops_away = true;

src/mesh/WarmNodeStore.cpp

@@ -0,0 +1,617 @@
+#include "WarmNodeStore.h"
+
+#if WARM_NODE_COUNT > 0
+
+#include "FSCommon.h"
+#include "SPILock.h"
+#include "SafeFile.h"
+#include "configuration.h"
+#include "power/PowerHAL.h"
+#include <ErriezCRC32.h>
+#include <vector>
+
+#if defined(NRF52840_XXAA)
+#include "flash/flash_nrf5x.h"
+#define WARM_RING_MAGIC 0x324E5257u    // "WRN2" — v2: last_heard low bits carry role + protected category
+#define WARM_RING_MAGIC_V1 0x474E5257u // "WRNG" — v1: last_heard was a plain timestamp.
+// v1 pages are still read on upgrade: we keep each record's identity + public key but
+// DISCARD its last_heard (the old timestamp would be misread as role/protected bits).
+// Records re-rank and re-learn their role on the next contact. Legacy pages convert to
+// v2 naturally as the ring rotates.
+// A tombstone is an entry record whose last_heard is all-ones — getTime()
+// (unix seconds) cannot reach 0xFFFFFFFF until 2106, and erased flash is
+// detected via num == 0xFFFFFFFF before last_heard is ever inspected.
+#define WARM_RING_TOMBSTONE 0xFFFFFFFFu
+#else
+// warm.dat layout: this header followed by count packed WarmNodeEntry records.
+struct WarmStoreHeader {
+    uint32_t magic;     // WARM_STORE_MAGIC
+    uint32_t reserved;  // 0; kept so the header stays 16 B
+    uint16_t count;     // entries persisted
+    uint16_t entrySize; // sizeof(WarmNodeEntry), format guard
+    uint32_t crc;       // crc32 over count * entrySize bytes
+};
+static_assert(sizeof(WarmStoreHeader) == 16, "header layout is part of the persistence format");
+
+#define WARM_STORE_MAGIC 0x324D5257u // "WRM2" — v2: last_heard low bits carry role + protected category
+#define WARM_STORE_MAGIC_V1                                                                                                      \
+    0x314D5257u // "WRM1" — v1: last_heard was a plain timestamp. On upgrade we keep
+                // identity + key but discard last_heard, then rewrite as v2.
+
+#ifdef FSCom
+static const char *warmFileName = "/prefs/warm.dat";
+#endif
+#endif // NRF52840_XXAA
+
+static inline bool keyIsSet(const uint8_t key[32])
+{
+    for (int i = 0; i < 32; i++)
+        if (key[i])
+            return true;
+    return false;
+}
+
+WarmNodeStore::WarmNodeStore()
+{
+#if defined(ARCH_ESP32) && defined(BOARD_HAS_PSRAM)
+    entries = static_cast<WarmNodeEntry *>(ps_calloc(WARM_NODE_COUNT, sizeof(WarmNodeEntry)));
+    if (!entries) {
+        LOG_WARN("WarmStore: PSRAM alloc failed, using heap");
+        entries = static_cast<WarmNodeEntry *>(calloc(WARM_NODE_COUNT, sizeof(WarmNodeEntry)));
+    }
+#else
+    entries = static_cast<WarmNodeEntry *>(calloc(WARM_NODE_COUNT, sizeof(WarmNodeEntry)));
+#endif
+#if defined(NRF52840_XXAA)
+    memset(pageOf, kNoPage, sizeof(pageOf));
+#endif
+}
+
+WarmNodeStore::~WarmNodeStore()
+{
+    free(entries); // always malloc-family (calloc / ps_calloc)
+    entries = nullptr;
+}
+
+WarmNodeEntry *WarmNodeStore::find(NodeNum num) const
+{
+    if (!entries || !num)
+        return nullptr;
+    for (size_t i = 0; i < WARM_NODE_COUNT; i++)
+        if (entries[i].num == num)
+            return &entries[i];
+    return nullptr;
+}
+
+// Slot placement with the keyed-first admission policy. Shared by absorb()
+// and the ring replay, so the policy is applied identically in both paths.
+WarmNodeEntry *WarmNodeStore::place(NodeNum num, uint32_t lastHeard, const uint8_t *key32)
+{
+    if (!entries || !num)
+        return nullptr;
+
+    const bool candidateKeyed = key32 && keyIsSet(key32);
+
+    WarmNodeEntry *slot = find(num);
+    const bool sameNode = slot != nullptr;
+    if (!slot) {
+        // Pick a victim: any empty slot, else the oldest keyless entry, else
+        // (only for keyed candidates) the oldest keyed entry.
+        WarmNodeEntry *oldestKeyless = nullptr, *oldestKeyed = nullptr;
+        for (size_t i = 0; i < WARM_NODE_COUNT; i++) {
+            WarmNodeEntry &e = entries[i];
+            if (!e.num) {
+                slot = &e;
+                break;
+            }
+            // Compare on the time bits only — the low metadata bits (role/protected) must
+            // not perturb LRU victim selection.
+            if (keyIsSet(e.public_key)) {
+                if (!oldestKeyed || warmTimeOf(e) < warmTimeOf(*oldestKeyed))
+                    oldestKeyed = &e;
+            } else {
+                if (!oldestKeyless || warmTimeOf(e) < warmTimeOf(*oldestKeyless))
+                    oldestKeyless = &e;
+            }
+        }
+        if (!slot)
+            slot = oldestKeyless ? oldestKeyless : (candidateKeyed ? oldestKeyed : nullptr);
+        if (!slot)
+            return nullptr; // store full of keyed entries and the candidate has no key
+    }
+
+    slot->num = num;
+    slot->last_heard = lastHeard;
+    if (candidateKeyed)
+        memcpy(slot->public_key, key32, 32);
+    else if (!sameNode)
+        // Repurposing a victim slot for a different node: clear its stale key.
+        // A keyless refresh of a node already here keeps the key we learned.
+        memset(slot->public_key, 0, 32);
+    return slot;
+}
+
+bool WarmNodeStore::absorb(NodeNum num, uint32_t lastHeard, const uint8_t *key32, uint8_t role, uint8_t protectedCat)
+{
+    // Pack role + protected category into the low bits of last_heard. place() and ring
+    // replay store the raw word verbatim, so the metadata round-trips through flash.
+    const uint32_t packed = warmPackLastHeard(lastHeard, role, protectedCat);
+    const WarmNodeEntry *slot = place(num, packed, key32);
+    if (!slot)
+        return false;
+    persistEntry(*slot);
+    LOG_MIGRATION("WarmStore absorb 0x%08x key=%d last_heard=%u role=%u prot=%u (now %u/%u)", (unsigned)num,
+                  keyIsSet(slot->public_key) ? 1 : 0, (unsigned)warmTimeOf(*slot), (unsigned)role, (unsigned)protectedCat,
+                  (unsigned)count(), (unsigned)capacity());
+    return true;
+}
+
+bool WarmNodeStore::lookupMeta(NodeNum num, uint8_t &role, uint8_t &protectedCat) const
+{
+    const WarmNodeEntry *e = find(num);
+    if (!e)
+        return false;
+    role = warmRoleOf(*e);
+    protectedCat = warmProtOf(*e);
+    return true;
+}
+
+bool WarmNodeStore::take(NodeNum num, WarmNodeEntry &out)
+{
+    WarmNodeEntry *e = find(num);
+    if (!e)
+        return false;
+    out = *e;
+    const int idx = static_cast<int>(e - entries);
+    memset(e, 0, sizeof(*e));
+    persistRemove(num, idx);
+    LOG_MIGRATION("WarmStore take(rehydrate) 0x%08x key=%d (now %u/%u)", (unsigned)num, keyIsSet(out.public_key) ? 1 : 0,
+                  (unsigned)count(), (unsigned)capacity());
+    return true;
+}
+
+#if MESHTASTIC_NODEDB_MIGRATION_VERBOSE
+void WarmNodeStore::dumpToLog(const char *reason) const
+{
+    if (!entries) {
+        LOG_MIGRATION("WarmStore dump (%s): backend not allocated", reason);
+        return;
+    }
+    LOG_MIGRATION("WarmStore dump (%s): %u live / %u cap ==>", reason, (unsigned)count(), (unsigned)capacity());
+    unsigned shown = 0;
+    for (size_t i = 0; i < WARM_NODE_COUNT; i++) {
+        const WarmNodeEntry &e = entries[i];
+        if (e.num == 0)
+            continue;
+        LOG_MIGRATION("  warm[%3u] 0x%08x last_heard=%u key=%d", (unsigned)i, (unsigned)e.num, (unsigned)e.last_heard,
+                      keyIsSet(e.public_key) ? 1 : 0);
+        shown++;
+    }
+    LOG_MIGRATION("WarmStore dump (%s): <== end (%u entries)", reason, shown);
+}
+#endif // MESHTASTIC_NODEDB_MIGRATION_VERBOSE
+
+bool WarmNodeStore::copyKey(NodeNum num, uint8_t out[32]) const
+{
+    const WarmNodeEntry *e = find(num);
+    if (!e || !keyIsSet(e->public_key))
+        return false;
+    memcpy(out, e->public_key, 32);
+    return true;
+}
+
+bool WarmNodeStore::contains(NodeNum num) const
+{
+    return find(num) != nullptr;
+}
+
+void WarmNodeStore::remove(NodeNum num)
+{
+    WarmNodeEntry *e = find(num);
+    if (e) {
+        const int idx = static_cast<int>(e - entries);
+        memset(e, 0, sizeof(*e));
+        persistRemove(num, idx);
+    }
+}
+
+void WarmNodeStore::clear()
+{
+    if (!entries)
+        return;
+    memset(entries, 0, WARM_NODE_COUNT * sizeof(WarmNodeEntry));
+#if defined(NRF52840_XXAA)
+    memset(pageOf, kNoPage, sizeof(pageOf));
+#endif
+    persistClear();
+}
+
+size_t WarmNodeStore::count() const
+{
+    size_t n = 0;
+    if (entries)
+        for (size_t i = 0; i < WARM_NODE_COUNT; i++)
+            if (entries[i].num)
+                n++;
+    return n;
+}
+
+bool WarmNodeStore::saveIfDirty()
+{
+    if (!dirty)
+        return true;
+    bool ok = save();
+    if (ok)
+        dirty = false;
+    return ok;
+}
+
+#if defined(NRF52840_XXAA)
+
+// Raw-flash record-ring backend (nRF52840).
+// 3 × 4 KB pages below LittleFS. Mutations append 40 B records (entry snapshot,
+// or tombstone with last_heard == 0xFFFFFFFF) via the shared flash_nrf5x page
+// cache; saveIfDirty() is the durability point. A full page reclaims the oldest
+// (stranded live entries re-appended, then erased). Flash access holds spiLock —
+// the page cache is shared with InternalFS/LittleFS.
+
+bool WarmNodeStore::ringReadHeader(uint8_t page, WarmPageHeader &h, bool *legacy) const
+{
+    flash_nrf5x_read(&h, WARM_FLASH_PAGE_ADDR(page), sizeof(h));
+    if (h.seq == 0xFFFFFFFFu)
+        return false; // erased page
+    if (h.magic == WARM_RING_MAGIC) {
+        if (legacy)
+            *legacy = false;
+        return true;
+    }
+    if (h.magic == WARM_RING_MAGIC_V1) {
+        if (legacy)
+            *legacy = true; // v1 page: replay it, but discard last_heard (see WARM_RING_MAGIC_V1)
+        return true;
+    }
+    return false;
+}
+
+// Caller holds spiLock.
+void WarmNodeStore::ringOpenPage(uint8_t page)
+{
+    // Drop any cached state for the page before the real erase, so a later
+    // cache flush can't resurrect stale bytes.
+    flash_nrf5x_flush();
+    flash_nrf5x_erase(WARM_FLASH_PAGE_ADDR(page));
+    WarmPageHeader h;
+    h.magic = WARM_RING_MAGIC;
+    h.seq = nextSeq++;
+    flash_nrf5x_write(WARM_FLASH_PAGE_ADDR(page), &h, sizeof(h));
+    activePage = page;
+    writeSlot = 0;
+}
+
+// Caller holds spiLock. May recurse once via ringAppend if the stranded set
+// fills the fresh page exactly — bounded by WARM_NODE_COUNT <= 2*kRecordsPerPage.
+void WarmNodeStore::ringRotate()
+{
+    uint8_t target = 0;
+    if (activePage != kNoPage) {
+        // Lowest-seq valid page, preferring erased pages; never the active one
+        uint32_t bestSeq = 0;
+        bool found = false;
+        for (uint8_t p = 0; p < WARM_FLASH_PAGES; p++) {
+            if (p == activePage)
+                continue;
+            WarmPageHeader h;
+            if (!ringReadHeader(p, h)) {
+                target = p; // erased/invalid page: free real estate, take it
+                found = true;
+                break;
+            }
+            if (!found || static_cast<int32_t>(h.seq - bestSeq) < 0) {
+                target = p;
+                bestSeq = h.seq;
+                found = true;
+            }
+        }
+    }
+
+    // Capture live entries stranded in the page we're about to erase
+    int stranded[WARM_NODE_COUNT] = {};
+    int nStranded = 0;
+    for (size_t i = 0; i < WARM_NODE_COUNT; i++) {
+        if (entries[i].num && pageOf[i] == target)
+            stranded[nStranded++] = static_cast<int>(i);
+        if (pageOf[i] == target)
+            pageOf[i] = kNoPage;
+    }
+
+    ringOpenPage(target);
+
+    for (int k = 0; k < nStranded; k++)
+        ringAppend(entries[stranded[k]], stranded[k]);
+}
+
+// Caller holds spiLock.
+void WarmNodeStore::ringAppend(const WarmNodeEntry &rec, int storeSlot)
+{
+    if (activePage == kNoPage || writeSlot >= kRecordsPerPage)
+        ringRotate();
+    const uint32_t addr =
+        WARM_FLASH_PAGE_ADDR(activePage) + sizeof(WarmPageHeader) + static_cast<uint32_t>(writeSlot) * sizeof(WarmNodeEntry);
+    flash_nrf5x_write(addr, &rec, sizeof(rec));
+    writeSlot++;
+    if (storeSlot >= 0)
+        pageOf[storeSlot] = activePage;
+    dirty = true;
+}
+
+void WarmNodeStore::persistEntry(const WarmNodeEntry &e)
+{
+    concurrency::LockGuard g(spiLock);
+    ringAppend(e, static_cast<int>(&e - entries));
+}
+
+void WarmNodeStore::persistRemove(NodeNum num, int storeSlot)
+{
+    if (storeSlot >= 0 && storeSlot < static_cast<int>(WARM_NODE_COUNT))
+        pageOf[storeSlot] = 0xFF;
+    WarmNodeEntry tomb;
+    memset(&tomb, 0, sizeof(tomb));
+    tomb.num = num;
+    tomb.last_heard = WARM_RING_TOMBSTONE;
+    concurrency::LockGuard g(spiLock);
+    ringAppend(tomb, -1);
+}
+
+void WarmNodeStore::persistClear()
+{
+    concurrency::LockGuard g(spiLock);
+    flash_nrf5x_flush();
+    for (uint8_t p = 0; p < WARM_FLASH_PAGES; p++)
+        flash_nrf5x_erase(WARM_FLASH_PAGE_ADDR(p));
+    activePage = 0xFF;
+    writeSlot = 0;
+    nextSeq = 1;
+    dirty = false; // the erased ring already reflects the empty store
+}
+
+void WarmNodeStore::load()
+{
+    if (!entries)
+        return;
+    concurrency::LockGuard g(spiLock);
+
+    // Order valid pages by ascending seq so replay applies oldest first
+    uint8_t order[WARM_FLASH_PAGES] = {};
+    uint32_t seqs[WARM_FLASH_PAGES] = {};
+    bool legacyOf[WARM_FLASH_PAGES] = {}; // per-page: v1 (WRNG) → discard last_heard on replay
+    uint8_t nValid = 0;
+    uint8_t nCorrupt = 0;
+    for (uint8_t p = 0; p < WARM_FLASH_PAGES; p++) {
+        WarmPageHeader h;
+        bool legacy = false;
+        if (!ringReadHeader(p, h, &legacy)) {
+            // An erased page reads back all-ones; any other magic is a
+            // partially-written or bit-rotted header we're dropping, so flag it
+            // rather than silently treating the loss as a clean empty ring.
+            if (h.magic != 0xFFFFFFFFu)
+                nCorrupt++;
+            continue;
+        }
+        legacyOf[p] = legacy;
+        uint8_t pos = nValid;
+        while (pos > 0 && static_cast<int32_t>(h.seq - seqs[pos - 1]) < 0) {
+            order[pos] = order[pos - 1];
+            seqs[pos] = seqs[pos - 1];
+            pos--;
+        }
+        order[pos] = p;
+        seqs[pos] = h.seq;
+        nValid++;
+    }
+
+    if (nValid == 0) {
+        activePage = 0xFF;
+        writeSlot = 0;
+        nextSeq = 1;
+        if (nCorrupt)
+            LOG_WARN("WarmStore: ring unreadable (%u bad page(s)), empty", nCorrupt);
+        else
+            LOG_INFO("WarmStore: ring empty, starting fresh");
+        return;
+    }
+
+    uint32_t replayed = 0;
+    uint32_t migrated = 0;
+    for (uint8_t k = 0; k < nValid; k++) {
+        const uint8_t p = order[k];
+        const bool legacy = legacyOf[p];
+        uint16_t slot = 0;
+        for (; slot < kRecordsPerPage; slot++) {
+            WarmNodeEntry rec;
+            flash_nrf5x_read(&rec, WARM_FLASH_PAGE_ADDR(p) + sizeof(WarmPageHeader) + (uint32_t)slot * sizeof(rec), sizeof(rec));
+            if (rec.num == 0xFFFFFFFFu)
+                break; // erased space: end of this page's records (append-only)
+            if (rec.num == 0)
+                continue; // unexpected; skip defensively
+            replayed++;
+            if (rec.last_heard == WARM_RING_TOMBSTONE) {
+                WarmNodeEntry *e = find(rec.num);
+                if (e) {
+                    pageOf[e - entries] = 0xFF;
+                    memset(e, 0, sizeof(*e));
+                }
+            } else {
+                // v1 (legacy) record: keep identity + key, but discard the old timestamp —
+                // its low bits would otherwise be misread as role/protected metadata.
+                uint32_t lh = rec.last_heard;
+                if (legacy) {
+                    lh = 0;
+                    migrated++;
+                }
+                const WarmNodeEntry *e = place(rec.num, lh, rec.public_key);
+                if (e)
+                    pageOf[e - entries] = p;
+            }
+        }
+        if (k == nValid - 1) { // newest page becomes the active head
+            activePage = p;
+            writeSlot = slot;
+            nextSeq = seqs[k] + 1;
+            // If the head is a v1 page, force the next append to rotate into a fresh v2 page,
+            // so new (v2) records never land in a page whose header says v1 (which would make
+            // a later load discard their last_heard — including the role/protected we just set).
+            if (legacy)
+                writeSlot = kRecordsPerPage;
+        }
+    }
+    if (nCorrupt)
+        LOG_WARN("WarmStore: dropped %u corrupt ring page(s), some nodes lost", nCorrupt);
+    if (migrated)
+        LOG_INFO("WarmStore: migrated %u v1 record(s) (kept key, discarded last_heard)", (unsigned)migrated);
+    LOG_INFO("WarmStore: replayed %u ring records -> %u live nodes (page %u, slot %u)", (unsigned)replayed, (unsigned)count(),
+             activePage, writeSlot);
+}
+
+bool WarmNodeStore::save()
+{
+    if (!powerHAL_isPowerLevelSafe()) {
+        LOG_ERROR("Error: trying to save WarmStore on unsafe device power level.");
+        return false;
+    }
+    concurrency::LockGuard g(spiLock);
+    flash_nrf5x_flush();
+    return true;
+}
+
+#else // !NRF52840_XXAA --------------------
+
+void WarmNodeStore::persistEntry(const WarmNodeEntry &e)
+{
+    (void)e;
+    dirty = true;
+}
+
+void WarmNodeStore::persistRemove(NodeNum num, int storeSlot)
+{
+    (void)num;
+    (void)storeSlot;
+    dirty = true;
+}
+
+void WarmNodeStore::persistClear()
+{
+    dirty = true;
+}
+
+#ifdef FSCom
+
+// ---- File persistence: /prefs/warm.dat snapshots ----------------------------
+
+// Compact occupied slots to the front of `dst`; returns the count.
+static uint16_t packEntries(const WarmNodeEntry *src, WarmNodeEntry *dst)
+{
+    uint16_t n = 0;
+    for (size_t i = 0; i < WARM_NODE_COUNT; i++)
+        if (src[i].num)
+            dst[n++] = src[i];
+    return n;
+}
+
+void WarmNodeStore::load()
+{
+    if (!entries)
+        return;
+    // Clear first — all failure paths below then correctly represent "empty",
+    // even if load() is called on an already-used instance.
+    memset(entries, 0, WARM_NODE_COUNT * sizeof(WarmNodeEntry));
+    concurrency::LockGuard g(spiLock);
+    auto f = FSCom.open(warmFileName, FILE_O_READ);
+    if (!f)
+        return;
+    WarmStoreHeader h;
+    if ((size_t)f.read((uint8_t *)&h, sizeof(h)) != sizeof(h)) {
+        f.close();
+        LOG_WARN("WarmStore: %s header read failed, starting empty", warmFileName);
+        return;
+    }
+    // v1 (WRM1) is still accepted: same record size, but its last_heard was a plain
+    // timestamp. We keep identity + key and discard last_heard on load (see below).
+    const bool legacy = (h.magic == WARM_STORE_MAGIC_V1);
+    if ((h.magic != WARM_STORE_MAGIC && !legacy) || h.entrySize != sizeof(WarmNodeEntry) || h.count > WARM_NODE_COUNT) {
+        f.close();
+        LOG_WARN("WarmStore: %s header invalid (magic=0x%08x entrySize=%u count=%u), starting empty", warmFileName, h.magic,
+                 h.entrySize, h.count);
+        return;
+    }
+    if (h.count) {
+        const size_t len = (size_t)h.count * sizeof(WarmNodeEntry);
+        const bool readOk = (size_t)f.read((uint8_t *)entries, len) == len;
+        f.close();
+        if (!readOk) {
+            LOG_WARN("WarmStore: %s entries read failed, starting empty", warmFileName);
+            return;
+        }
+        // CRC covers the bytes as written (v1 still has the old last_heard), so check before migrating.
+        if (crc32Buffer(entries, len) != h.crc) {
+            LOG_WARN("WarmStore: %s CRC mismatch, starting empty", warmFileName);
+            memset(entries, 0, WARM_NODE_COUNT * sizeof(WarmNodeEntry));
+            return;
+        }
+        if (legacy) {
+            // Migrate v1 → v2: discard the old last_heard (its low bits would be misread as
+            // role/protected); keep num + public_key. Mark dirty so save() rewrites as v2.
+            for (size_t i = 0; i < WARM_NODE_COUNT; i++)
+                if (entries[i].num)
+                    entries[i].last_heard = 0;
+            dirty = true;
+        }
+    } else {
+        f.close();
+    }
+    LOG_INFO("WarmStore: loaded %u warm nodes from %s%s", h.count, warmFileName,
+             legacy ? " (v1 migrated: discarded last_heard)" : "");
+}
+
+bool WarmNodeStore::save()
+{
+    if (!entries)
+        return false;
+    if (!powerHAL_isPowerLevelSafe()) {
+        LOG_ERROR("Error: trying to save WarmStore on unsafe device power level.");
+        return false;
+    }
+
+    std::vector<WarmNodeEntry> packed(WARM_NODE_COUNT);
+    WarmStoreHeader h;
+    h.magic = WARM_STORE_MAGIC;
+    h.reserved = 0;
+    h.count = packEntries(entries, packed.data());
+    h.entrySize = sizeof(WarmNodeEntry);
+    h.crc = crc32Buffer(packed.data(), h.count * sizeof(WarmNodeEntry));
+
+    concurrency::LockGuard g(spiLock);
+    FSCom.mkdir("/prefs");
+
+    auto f = SafeFile(warmFileName, false);
+    f.write((const uint8_t *)&h, sizeof(h));
+    f.write((const uint8_t *)packed.data(), h.count * sizeof(WarmNodeEntry));
+    bool ok = f.close();
+    if (!ok)
+        LOG_ERROR("WarmStore: can't write %s", warmFileName);
+    else
+        LOG_DEBUG("WarmStore: saved %u warm nodes to %s", h.count, warmFileName);
+    return ok;
+}
+
+#else
+
+void WarmNodeStore::load() {}
+bool WarmNodeStore::save()
+{
+    return true;
+}
+
+#endif // FSCom
+#endif // NRF52840_XXAA
+
+#endif // WARM_NODE_COUNT > 0

src/mesh/WarmNodeStore.h

@@ -0,0 +1,176 @@
+#pragma once
+
+#include "MeshTypes.h"
+#include "mesh-pb-constants.h"
+#include <stdint.h>
+#include <string.h>
+
+// Verbose tracing for the warm-store migration + NodeDB self-care. Per-event /
+// per-boot chatter routes through this so it can be silenced in one place (set
+// to 0) once they're proven; genuine LOG_WARN anomalies stay unconditional.
+#ifndef MESHTASTIC_NODEDB_MIGRATION_VERBOSE
+#define MESHTASTIC_NODEDB_MIGRATION_VERBOSE 0
+#endif
+#if MESHTASTIC_NODEDB_MIGRATION_VERBOSE
+#define LOG_MIGRATION(...) LOG_INFO(__VA_ARGS__)
+#else
+#define LOG_MIGRATION(...) ((void)0)
+#endif
+
+#if WARM_NODE_COUNT > 0
+
+/**
+ * Warm ("long-tail") node tier.
+ *
+ * Minimal identity record (NodeNum, last_heard, Curve25519 public key) for nodes
+ * evicted from the hot NodeInfoLite store, so DMs to/from them keep encrypting —
+ * the key is expensive to re-learn, the rest rebuilds from traffic in seconds.
+ * Flat fixed array, linear scan (only on hot-store misses), LRU by last_heard
+ * with keyed entries outranking keyless.
+ *
+ * Persistence: nRF52840 uses a 12 KB raw-flash record-ring below LittleFS
+ * (append + replay + compact-on-rotate — see the backend in WarmNodeStore.cpp,
+ * link-guarded by nrf52840_s140_v7.ld). Everywhere else: /prefs/warm.dat.
+ */
+struct WarmNodeEntry {
+    NodeNum num;            // 0 = empty slot
+    uint32_t last_heard;    // recency for LRU ordering — see the metadata steal below
+    uint8_t public_key[32]; // all-zero = no key (a real key is never all-zero)
+};
+static_assert(sizeof(WarmNodeEntry) == 40, "WarmNodeEntry must stay 40 B — persistence format depends on it");
+
+// Metadata packed into the low bits of last_heard.
+//
+// The warm tier only uses last_heard to LRU-rank evicted (long-tail) nodes, so ~minute
+// recency resolution is plenty. We reclaim the low WARM_META_BITS of that field to carry
+// the evicted node's device role + a protected category, at zero cost to record size
+// (entry stays 40 B; no RAM/flash growth). The high bits remain a real unix-seconds
+// timestamp quantised to (1 << WARM_META_BITS) seconds.
+//
+// Safe because: a real timestamp can never be all-ones (the tombstone sentinel) before
+// 2106, and tombstones/erased flash are detected via num before last_heard is read. Only
+// the LOW bits are stolen — the high (era) bits are untouched, so the time range is intact.
+static constexpr uint32_t WARM_META_BITS = 6;                          // role(4) + protected(2)
+static constexpr uint32_t WARM_META_MASK = (1u << WARM_META_BITS) - 1; // 0x3F → 64 s quantum
+static constexpr uint32_t WARM_TIME_MASK = ~WARM_META_MASK;            // 0xFFFFFFC0
+static constexpr uint32_t WARM_ROLE_MASK = 0x0Fu;                      // bits [3:0] device role (0..12)
+static constexpr uint32_t WARM_PROT_SHIFT = 4;                         // bits [5:4] protected category
+static constexpr uint32_t WARM_PROT_MASK = 0x03u;
+
+// Protected category cached alongside role so consumers needn't re-derive the mapping.
+enum class WarmProtected : uint8_t { None = 0, Role = 1, Flag = 2 };
+
+inline uint32_t warmPackLastHeard(uint32_t lastHeard, uint8_t role, uint8_t prot)
+{
+    return (lastHeard & WARM_TIME_MASK) | (static_cast<uint32_t>(role) & WARM_ROLE_MASK) |
+           ((static_cast<uint32_t>(prot) & WARM_PROT_MASK) << WARM_PROT_SHIFT);
+}
+inline uint32_t warmTimeOf(const WarmNodeEntry &e)
+{
+    return e.last_heard & WARM_TIME_MASK;
+}
+inline uint8_t warmRoleOf(const WarmNodeEntry &e)
+{
+    return static_cast<uint8_t>(e.last_heard & WARM_ROLE_MASK);
+}
+inline uint8_t warmProtOf(const WarmNodeEntry &e)
+{
+    return static_cast<uint8_t>((e.last_heard >> WARM_PROT_SHIFT) & WARM_PROT_MASK);
+}
+
+// Gated on NRF52840_XXAA: the ring sits at 0xEA000
+// valid only on the 1 MB-flash nRF52840.
+#if defined(NRF52840_XXAA)
+#define WARM_FLASH_PAGE_SIZE 4096u
+#define WARM_FLASH_PAGES 3u
+#define WARM_FLASH_REGION_BASE (0xED000u - WARM_FLASH_PAGES * WARM_FLASH_PAGE_SIZE) // 0xEA000
+#define WARM_FLASH_PAGE_ADDR(i) (WARM_FLASH_REGION_BASE + (i)*WARM_FLASH_PAGE_SIZE)
+#endif
+
+class WarmNodeStore
+{
+  public:
+    WarmNodeStore();
+    ~WarmNodeStore();
+    WarmNodeStore(const WarmNodeStore &) = delete;
+    WarmNodeStore &operator=(const WarmNodeStore &) = delete;
+
+    /// Remember an evicted hot node. Keyless candidates never displace keyed
+    /// entries; otherwise the oldest (keyless-first) entry is replaced.
+    /// @param role         the node's device role (meshtastic_Config_DeviceConfig_Role, 0..12)
+    /// @param protectedCat WarmProtected category cached for the hop-trim path
+    /// @return true if the node was stored or updated
+    bool absorb(NodeNum num, uint32_t lastHeard, const uint8_t *key32 /* may be NULL */, uint8_t role = 0,
+                uint8_t protectedCat = 0);
+
+    /// Look up the cached device role + protected category for a warm node.
+    /// @return false if the node is not in the warm tier.
+    bool lookupMeta(NodeNum num, uint8_t &role, uint8_t &protectedCat) const;
+
+    /// Find and remove an entry (used when the node is re-admitted to the hot store).
+    bool take(NodeNum num, WarmNodeEntry &out);
+
+    /// Copy the 32-byte public key for a node, if we have one.
+    bool copyKey(NodeNum num, uint8_t out[32]) const;
+
+    bool contains(NodeNum num) const;
+    void remove(NodeNum num);
+    void clear();
+    size_t count() const;
+    size_t capacity() const { return entries ? WARM_NODE_COUNT : 0; }
+
+#if MESHTASTIC_NODEDB_MIGRATION_VERBOSE
+    /// Debug: dump every live warm entry (num / last_heard / has-key) to the
+    /// console. Compiled out unless MESHTASTIC_NODEDB_MIGRATION_VERBOSE.
+    void dumpToLog(const char *reason = "dump") const;
+#endif
+
+    /// Load persisted entries (called once at boot, after the node DB loads).
+    void load();
+    /// Durability point, piggybacked on the node-database save cadence. On the
+    /// ring backend this flushes the shared flash page cache; on the file
+    /// backend it writes the warm.dat snapshot.
+    bool saveIfDirty();
+
+  private:
+    WarmNodeEntry *entries = nullptr; // WARM_NODE_COUNT slots; PSRAM on ESP32 when available
+    bool dirty = false;
+
+    WarmNodeEntry *find(NodeNum num) const;
+    // Internal slot-placement shared by absorb() and ring replay: applies the
+    // keyed-first admission policy without touching persistence.
+    WarmNodeEntry *place(NodeNum num, uint32_t lastHeard, const uint8_t *key32);
+
+    // Persistence hooks called from the mutation paths. File backend: mark
+    // dirty. Ring backend: append an upsert/tombstone record (+ mark dirty).
+    void persistEntry(const WarmNodeEntry &e); // e must point into entries[]
+    void persistRemove(NodeNum num, int storeSlot);
+    void persistClear();
+
+#if defined(NRF52840_XXAA)
+    // nRF52840 raw-flash record-ring state.
+    struct WarmPageHeader {
+        uint32_t magic; // WARM_RING_MAGIC
+        uint32_t seq;   // page generation; 0xFFFFFFFF = erased/unused
+    };
+    static_assert(sizeof(WarmPageHeader) == 8, "page header is part of the flash format");
+    static constexpr uint16_t kRecordsPerPage = (WARM_FLASH_PAGE_SIZE - sizeof(WarmPageHeader)) / sizeof(WarmNodeEntry); // 102
+    static_assert(WARM_NODE_COUNT <= 2 * ((WARM_FLASH_PAGE_SIZE - 8) / 40), "live set must fit the ring with one page reclaimed");
+
+    static constexpr uint8_t kNoPage = 0xFF; // "no page" sentinel for activePage / pageOf[]
+
+    uint8_t activePage = kNoPage;    // no page opened yet (fresh/erased ring)
+    uint16_t writeSlot = 0;          // next free record slot in the active page
+    uint32_t nextSeq = 1;            // seq for the next page opened
+    uint8_t pageOf[WARM_NODE_COUNT]; // flash page holding each RAM slot's newest record; kNoPage = none
+
+    void ringAppend(const WarmNodeEntry &rec, int storeSlot /* -1 for tombstones */);
+    void ringRotate();               // reclaim oldest page, compacting stranded live entries
+    void ringOpenPage(uint8_t page); // erase + write header (seq = nextSeq++)
+    bool ringReadHeader(uint8_t page, WarmPageHeader &h, bool *legacy = nullptr) const;
+#endif
+
+    bool save();
+};
+
+#endif // WARM_NODE_COUNT > 0