diff --git a/src/platform/nrf52/NRF52Bluetooth.cpp b/src/platform/nrf52/NRF52Bluetooth.cpp
index deecf65ec..dd0230100 100644
--- a/src/platform/nrf52/NRF52Bluetooth.cpp
+++ b/src/platform/nrf52/NRF52Bluetooth.cpp
@@ -4,6 +4,7 @@
 #include "HardwareRNG.h"
 #include "PowerFSM.h"
 #include "configuration.h"
+#include "error.h"
 #include "main.h"
 #include "mesh/PhoneAPI.h"
 #include "mesh/mesh-pb-constants.h"
@@ -275,7 +276,16 @@ void NRF52Bluetooth::setup()
     LOG_INFO("Init the Bluefruit nRF52 module");
     Bluefruit.autoConnLed(false);
     Bluefruit.configPrphBandwidth(BANDWIDTH_MAX);
-    Bluefruit.begin();
+    if (!Bluefruit.begin()) {
+        // sd_ble_enable() rejected our RAM base: the linker RAM ORIGIN
+        // (src/platform/nrf52/nrf52840_s140_v*.ld) is below what the SoftDevice needs for the
+        // current Bluefruit config. Without this check the node would silently run without BLE.
+        // Rebuild with -DCFG_DEBUG=1 to get "SoftDevice's RAM requires: 0x..." in the log, then
+        // raise the ORIGIN accordingly.
+        LOG_ERROR("Bluefruit.begin failed - SoftDevice RAM reservation too small for this config");
+        RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_UNSPECIFIED);
+        return;
+    }
     // Clear existing data.
     Bluefruit.Advertising.stop();
     Bluefruit.Advertising.clearData();
diff --git a/src/platform/nrf52/nrf52840_s140_v6.ld b/src/platform/nrf52/nrf52840_s140_v6.ld
index c8dac4e55..a956c6583 100644
--- a/src/platform/nrf52/nrf52840_s140_v6.ld
+++ b/src/platform/nrf52/nrf52840_s140_v6.ld
@@ -21,8 +21,17 @@ MEMORY
    * - Max ATT MTU
    * - Concurrent connection peripheral + central + secure links
    * - Event Len, HVN queue, Write CMD queue
+   *
+   * With our fixed Bluefruit config (1 peripheral link, BANDWIDTH_MAX / MTU 247,
+   * 0x1000 attr table) sd_ble_enable() reports a requirement well below the old
+   * 0x20006000 ORIGIN; every byte of gap is unusable RAM. 0x20004000 keeps a
+   * ~2+ KB margin over the reported base. NRF52Bluetooth::setup() now checks
+   * Bluefruit.begin() and records a critical error if the SoftDevice ever
+   * rejects this base (e.g. after an SD/Bluefruit config change) - re-measure
+   * with CFG_DEBUG=1 (Bluefruit logs "SoftDevice's RAM requires: 0x...")
+   * before raising bandwidth/MTU/link settings.
    */
-  RAM (rwx) :  ORIGIN = 0x20006000, LENGTH = 0x20040000 - 0x20006000
+  RAM (rwx) :  ORIGIN = 0x20004000, LENGTH = 0x20040000 - 0x20004000
 }
 
 SECTIONS
diff --git a/src/platform/nrf52/nrf52840_s140_v7.ld b/src/platform/nrf52/nrf52840_s140_v7.ld
index 4546b4a7a..dbaf7dfb7 100644
--- a/src/platform/nrf52/nrf52840_s140_v7.ld
+++ b/src/platform/nrf52/nrf52840_s140_v7.ld
@@ -18,8 +18,17 @@ MEMORY
    * - Max ATT MTU
    * - Concurrent connection peripheral + central + secure links
    * - Event Len, HVN queue, Write CMD queue
-   */ 
-  RAM (rwx) :  ORIGIN = 0x20006000, LENGTH = 0x20040000 - 0x20006000
+   *
+   * With our fixed Bluefruit config (1 peripheral link, BANDWIDTH_MAX / MTU 247,
+   * 0x1000 attr table) sd_ble_enable() reports a requirement well below the old
+   * 0x20006000 ORIGIN; every byte of gap is unusable RAM. 0x20004000 keeps a
+   * ~2+ KB margin over the reported base. NRF52Bluetooth::setup() now checks
+   * Bluefruit.begin() and records a critical error if the SoftDevice ever
+   * rejects this base (e.g. after an SD/Bluefruit config change) - re-measure
+   * with CFG_DEBUG=1 (Bluefruit logs "SoftDevice's RAM requires: 0x...")
+   * before raising bandwidth/MTU/link settings.
+   */
+  RAM (rwx) :  ORIGIN = 0x20004000, LENGTH = 0x20040000 - 0x20004000
 }
 
 SECTIONS