diff --git a/bin/platformio-custom.py b/bin/platformio-custom.py
index f1946770c..0990faab6 100644
--- a/bin/platformio-custom.py
+++ b/bin/platformio-custom.py
@@ -219,41 +219,37 @@ with open(jsonLoc) as f:
     jsonStr = re.sub("//.*","", f.read(), flags=re.MULTILINE)
     userPrefs = json.loads(jsonStr)
 
-pref_flags = []
-# Pre-process the userPrefs
-for pref in userPrefs:
-    if userPrefs[pref].startswith("{"):
-        pref_flags.append("-D" + pref + "=" + userPrefs[pref])
-    elif userPrefs[pref].lstrip("-").replace(".", "").isdigit():
-        pref_flags.append("-D" + pref + "=" + userPrefs[pref])
-    elif userPrefs[pref] == "true" or userPrefs[pref] == "false":
-        pref_flags.append("-D" + pref + "=" + userPrefs[pref])
-    elif userPrefs[pref].startswith("meshtastic_"):
-        pref_flags.append("-D" + pref + "=" + userPrefs[pref])
-    # If the value is a string, we need to wrap it in quotes
-    else:
-        pref_flags.append("-D" + pref + "=" + env.StringifyMacro(userPrefs[pref]) + "")
-
-# General options that are passed to the C and C++ compilers
 # Calculate unix epoch for current day (midnight)
 current_date = datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)
 build_epoch = int(current_date.timestamp())
 
-flags = [
-        "-DAPP_VERSION=" + verObj["long"],
-        "-DAPP_VERSION_SHORT=" + verObj["short"],
-        "-DAPP_ENV=" + env.get("PIOENV"),
-        "-DAPP_REPO=" + repo_owner,
-        "-DBUILD_EPOCH=" + str(build_epoch),
-    ] + pref_flags
+cpp_defines = [
+    ("APP_VERSION", verObj["long"]),
+    ("APP_VERSION_SHORT", verObj["short"]),
+    ("APP_ENV", env.get("PIOENV")),
+    ("APP_REPO", repo_owner),
+    ("BUILD_EPOCH", str(build_epoch)),
+]
 
-print("Using flags:")
-for flag in flags:
-    print(flag)
+# Process userPrefs into CPPDEFINES
+for pref in userPrefs:
+    val = userPrefs[pref]
+    if val.startswith("{"):
+        cpp_defines.append((pref, val))
+    elif val.lstrip("-").replace(".", "").isdigit():
+        cpp_defines.append((pref, val))
+    elif val == "true" or val == "false":
+        cpp_defines.append((pref, val))
+    elif val.startswith("meshtastic_"):
+        cpp_defines.append((pref, val))
+    else:
+        cpp_defines.append((pref, env.StringifyMacro(val)))
 
-projenv.Append(
-    CCFLAGS=flags,
-)
+print("Using CPPDEFINES:")
+for d in cpp_defines:
+    print(f"  -D{d[0]}={d[1]}")
+
+projenv.Append(CPPDEFINES=cpp_defines)
 
 for lb in env.GetLibBuilders():
     if lb.name == "meshtastic-device-ui":
diff --git a/platformio.ini b/platformio.ini
index d9c685e8b..7d5f9b24c 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -13,7 +13,7 @@ extra_configs =
 description = Meshtastic
 
 [env]
-test_build_src = true
+; test_build_src = true  ; disabled for faster incremental builds
 extra_scripts =
 	pre:bin/platformio-pre.py
 	bin/platformio-custom.py