diff --git a/local_build.sh b/local_build.sh
index d70d65408..5f0987a0d 100755
--- a/local_build.sh
+++ b/local_build.sh
@@ -8,7 +8,7 @@
 # Defaults baked in (edit the list below to change them):
 #   Radio  919.5 MHz / BW500 / SF10 / CR5  (matches the local mesh;
 #          Hazelwood KM-Test repeater)
-#   BLE    PIN code macro 123456 (on display boards such as Heltec V3 the
+#   BLE    PIN code macro 123456, companion targets only (on display boards such as Heltec V3 the
 #          firmware treats 123456 as "show a random PIN on screen each
 #          session"; set a fixed PIN at runtime from the app/CLI instead)
 #   Settings profile: target defaults (--profile default), not Cascade
@@ -29,7 +29,13 @@
 
 set -e
 
-LOCAL_BUILD_FLAGS="-DLORA_FREQ=919.5 -DLORA_BW=500 -DLORA_SF=10 -DLORA_CR=5 -DBLE_PIN_CODE=123456"
+LOCAL_BUILD_FLAGS="-DLORA_FREQ=919.5 -DLORA_BW=500 -DLORA_SF=10 -DLORA_CR=5"
+# BLE_PIN_CODE only matters to companions. scripts/check_firmware_ram.py
+# reserves 5,920 bytes of Bluetooth worker stacks on nRF52 whenever it is
+# defined, which pushes the RAK4631 repeater over its runtime RAM budget.
+case "${2:-}" in
+  *companion*) LOCAL_BUILD_FLAGS="${LOCAL_BUILD_FLAGS} -DBLE_PIN_CODE=123456" ;;
+esac
 
 export PLATFORMIO_BUILD_FLAGS="${PLATFORMIO_BUILD_FLAGS:+${PLATFORMIO_BUILD_FLAGS} }${LOCAL_BUILD_FLAGS}"