Retain GPS in RAK nRF52 OTA repeaters

docs/cli_build_matrix.md

@@ -41,7 +41,7 @@ retain 50 because their MQTT discovery tables are constrained by internal DRAM.
 | ESP32 MQTT observer or ESP-NOW bridge | Always uses the expanded FULL partition profile. The build never substitutes a reduced CLI to fit the legacy application slot. |
 | FULL ESP32 | Uses the matching MQTT target with logging off and keeps the complete command surface supported by that role and hardware. |
 | FULL ESP32 logging | Uses the matching non-MQTT target with debug and packet logging enabled, session-only `get/set usb.logging` control, and the complete command surface supported by that role and hardware. |
-| `no_external_sensors` | Removes optional external-sensor drivers and their settings; it does not remove core repeater discovery or routing commands. On RAK3401, this profile also compiles out GPS, so RAK12501 requires the ordinary full-sensor build. |
+| `no_external_sensors` | Removes optional external-sensor drivers and their settings; it does not remove core repeater discovery or routing commands. GPS-preserving RAK nRF52 OTA profiles retain their GPS commands and provider. The RAK4631 Serial1 RS232 bridge remains GPS-off because both features require Serial1. |
 
 `logging`, `OTA`, and `FULL` describe independent build features. Do not infer
 that a command is missing merely because `logging` appears in the filename.

docs/ota_easy.md

@@ -68,12 +68,10 @@ overlapping window.
 `build.sh` provides a `*_repeater_lora_ota_no_external_sensors` build for standalone ESP32 and nRF52 repeater
 targets that need a smaller internal update workspace. Those siblings omit optional external I2C
 environmental sensors while retaining board-native features such as displays, buttons, battery monitoring,
-and integrated GPS where the target uses the GPS-preserving lean profile. The
-RAK3401 target is an explicit exception:
-`RAK_3401_repeater_lora_ota_no_external_sensors` compiles out GPS and cannot
-use a RAK12501. Use the ordinary full-sensor `RAK_3401_repeater` build with a
-RAK12501 in sensor slot A when GPS is required; slot D conflicts with the
-RAK13302 radio's BUSY/DIO1 lines. Selected nRF52 boards with matched external
+and GPS where the target uses the GPS-preserving lean profile. The RAK3401 OTA
+repeater retains RAK12501 support in sensor slot A; slot D conflicts with the
+RAK13302 radio's BUSY/DIO1 lines. The RAK4631 OTA repeater retains GPS except
+for its Serial1 RS232 bridge, which uses the same UART. Selected nRF52 boards with matched external
 QSPI application and bootloader support can instead make the normal full-sensor
 repeater install-capable; those targets do not need to reserve internal flash
 for the downloaded container. Other normal repeaters can still serve as

docs/ota_nrf52_bootloader_update.md

@@ -142,10 +142,10 @@ stable release uses `0xFF`, and low-byte zero or all-ones values are rejected.
 There is no remote rollback/migration override; intentional rollback uses
 USB/BLE DFU or SWD.
 
-The `no_external_sensors` profiles omit optional/add-on sensor and GPS packages
-to preserve flash headroom. Board-integrated GPS can be retained by a board's
-recipe. The RAK3401 lean target specifically omits RAK12501/add-on GPS; use the
-ordinary full-sensor target when that module is required.
+The `no_external_sensors` profiles omit optional/add-on sensor packages to
+preserve flash headroom. A board recipe can retain GPS. The RAK3401 OTA
+repeater retains RAK12501 GPS in sensor slot A, and the RAK4631 OTA repeater
+retains GPS except where a Serial1 RS232 bridge owns the same UART.
 
 Boards with onboard external flash are not silently redirected to internal
 staging. Mesh Solar, Nano G2 Ultra, T-Impulse Plus, ThinkNode M8, T-Echo

docs/ota_protocol.md

@@ -128,10 +128,10 @@ established target-specific 1920 KiB or larger A/B app layout and are checked ag
 partition. For every standalone ESP32 and nRF52 repeater, `build.sh` also exposes an explicit
 `*_lora_ota_no_external_sensors` artifact: the ordinary repeater remains sensor-enabled, while that sibling
 disables optional external environmental-sensor drivers for LoRa distribution. Integrated GPS and other
-board-native telemetry remain enabled where the target selects the GPS-preserving lean profile. RAK3401 is
-the explicit exception: `RAK_3401_repeater_lora_ota_no_external_sensors` undefines `ENV_INCLUDE_GPS`, so it
-does not detect or use a RAK12501. RAK12501 GPS requires the ordinary full-sensor `RAK_3401_repeater` build
-and sensor slot A; slot D conflicts with the RAK13302 radio's BUSY/DIO1 lines.
+board-native telemetry remain enabled where the target selects the GPS-preserving lean profile. The RAK3401
+OTA repeater also retains RAK12501 GPS support; install that module in sensor slot A because slot D conflicts
+with the RAK13302 radio's BUSY/DIO1 lines. RAK4631 OTA repeaters retain GPS except for the Serial1 RS232
+bridge, whose bridge and GPS would contend for the same UART.
 ESP32 siblings retain the compact browser WiFi updater and use the full
 254-entry neighbor table. RP2040 and STM32 targets are not offered because
 those platforms do not yet have a safe bootloader/apply path.

docs/ota_user_guide.md

@@ -39,14 +39,15 @@ install-capable `lora_ota_no_external_sensors` sibling is smaller:
 - Keepteen LT1, LilyGo T-Impulse Plus, Mesh Pocket, and Nano G2 Ultra
 - Minewsemi ME25LS01, RAK3401, SenseCAP Solar, and Wio WM1110
 
-RAK3401 is an important GPS exception: its
-`RAK_3401_repeater_lora_ota_no_external_sensors` image compiles out GPS support
-as well as the optional environmental sensors. It will not detect or use a
-RAK12501. For RAK12501 GPS, use the ordinary full-sensor
-`RAK_3401_repeater` build and install the GPS in sensor slot A. Slot D's GPS
-reset/PPS lines conflict with the RAK13302 radio's BUSY/DIO1 lines. The
-full-sensor RAK3401 build is not the self-updating target described by the
-RAK3401 compact OTA chain.
+The RAK3401 `RAK_3401_repeater_lora_ota_no_external_sensors` image retains
+RAK12501 GPS while omitting the other optional environmental sensors. Install
+the GPS in sensor slot A. Slot D's reset/PPS lines conflict with the RAK13302
+radio's BUSY/DIO1 lines.
+
+The RAK4631 internal-flash OTA repeater likewise retains GPS. A RAK12501 can
+use sensor slot A or D; a RAK12500 can use slot A or C. The RAK4631 Serial1
+RS232 OTA bridge is the exception because the bridge owns the GPS UART. The
+Serial2 RS232 OTA bridge retains GPS on Serial1.
 
 Selected nRF52 repeaters with dedicated external QSPI can now stage the
 complete package off-chip, so their normal full-sensor repeater build can

docs/rak3401_mota_chain.md

@@ -34,7 +34,7 @@ target:
 - endpoint packed version: `0x01110102` (EndF tools render this as `1.17.1.2`)
 - deployment target key: `63d8df6387eaffd2e25db7d2a8ad967a65202182a48d681d7e7a9260f917280d`
 
-### GPS limitation
+### Historical endpoint GPS limitation
 
 This chain's exact `RAK_3401_repeater_lora_ota_no_external_sensors` endpoint
 compiles with `ENV_INCLUDE_GPS` removed. It will not detect, configure, or read
@@ -44,6 +44,10 @@ A. Do not use slot D with the RAK13302 1 W radio: the GPS reset/PPS signals
 would overlap the radio's BUSY/DIO1 signals. The full-sensor build is a
 different target and is not an endpoint of this compact OTA chain.
 
+This limitation describes the immutable released chain endpoint identified
+above. Newly built RAK3401 OTA repeater firmware retains RAK12501 support in
+slot A, but that newer image is not retroactively part of this exact chain.
+
 Do not use the chain on another target ID, hardware family, starting image, or
 firmware body hash. The runner checks all four.
 

tools/mota/test_mota.py

@@ -79,6 +79,38 @@ def test_ota_target_generation_honors_explicit_disable():
     assert "RAK_3401_repeater_lora_ota_no_external_sensors" in release_aliases()
 
 
+def test_rak_nrf52_ota_profiles_keep_gps_where_uart_is_available():
+    root = Path(__file__).resolve().parents[2]
+
+    def env_section(path, name):
+        text = path.read_text(encoding="utf-8")
+        return text.split(f"[env:{name}]", 1)[1].split("\n[", 1)[0]
+
+    rak4631_path = root / "variants/rak4631/platformio.ini"
+    gps_profiles = (
+        env_section(rak4631_path, "RAK_4631_repeater_lora_ota_no_external_sensors"),
+        env_section(
+            rak4631_path,
+            "RAK_4631_repeater_bridge_rs232_serial2_lora_ota_no_external_sensors",
+        ),
+        env_section(
+            root / "variants/rak3401/platformio.ini",
+            "RAK_3401_repeater_lora_ota_no_external_sensors",
+        ),
+    )
+    for profile in gps_profiles:
+        assert "${nrf52_no_external_sensors_keep_gps.build_flags}" in profile
+        assert "${nrf52_no_external_sensors_keep_gps.lib_deps}" in profile
+        assert "SparkFun u-blox GNSS Arduino Library" in profile
+
+    serial1_bridge = env_section(
+        rak4631_path,
+        "RAK_4631_repeater_bridge_rs232_serial1_lora_ota_no_external_sensors",
+    )
+    assert "${nrf52_no_external_sensors.build_flags}" in serial1_bridge
+    assert "WITH_RS232_BRIDGE=Serial1" in serial1_bridge
+
+
 def test_hardware_id_for_env():
     assert ml.hardware_id_for_env("RAK_4631_repeater") == "RAK4631"
     assert ml.hardware_id_for_env("RAK_4631_companion_radio_usb") == "RAK4631"

variants/rak3401/platformio.ini

@@ -48,15 +48,15 @@ build_src_filter = ${rak3401.build_src_filter}
   +<helpers/ui/SSD1306Display.cpp>
   +<../examples/simple_repeater>
 
-; Explicit lean alternative to the full-sensor, non-OTA repeater above. This
-; profile also removes ENV_INCLUDE_GPS: use RAK_3401_repeater with a RAK12501
-; in sensor slot A when GPS is required (slot D conflicts with radio BUSY/DIO1).
+; Explicit lean alternative to the full-sensor, non-OTA repeater above. It removes optional
+; environmental sensors while retaining RAK12501 GPS support. Use sensor slot A: slot D conflicts
+; with the RAK13302 radio's BUSY/DIO1 wiring. The legacy target name remains stable for OTA compatibility.
 [env:RAK_3401_repeater_lora_ota_no_external_sensors]
 extends = rak3401
 extra_scripts = ${nrf52_lora_ota.extra_scripts}
 build_flags =
   ${rak3401.build_flags}
-  ${nrf52_no_external_sensors.build_flags}
+  ${nrf52_no_external_sensors_keep_gps.build_flags}
   -D DISPLAY_CLASS=SSD1306Display
   -D ADVERT_NAME='"RAK3401 1W Repeater"'
   -D ADVERT_LAT=0.0
@@ -76,7 +76,9 @@ build_src_filter = ${rak3401.build_src_filter}
   +<../examples/simple_repeater>
 lib_deps =
   ${nrf52_lora_ota.lib_deps}
+  ${nrf52_no_external_sensors_keep_gps.lib_deps}
   adafruit/Adafruit SSD1306 @ ^2.5.13
+  sparkfun/SparkFun u-blox GNSS Arduino Library@^2.2.27
 
 [env:RAK_3401_room_server]
 extends = rak3401

variants/rak4631/platformio.ini

@@ -87,15 +87,16 @@ build_src_filter = ${rak4631.build_src_filter}
   +<helpers/ui/SSD1306Display.cpp>
   +<../examples/simple_repeater>
 
-; Lean OTA target for space-constrained RAK4631 repeaters. This removes only optional external
-; environmental/GPS sensor packages. RAK4631Board::getBattMilliVolts(), repeater telemetry, and
-; battery.alert remain part of the board/repeater sources below.
+; Lean OTA target for space-constrained RAK4631 repeaters. This removes optional external
+; environmental sensor packages while retaining RAK12500/RAK12501 GPS support. The legacy
+; no_external_sensors target name remains stable for OTA compatibility. RAK4631Board::getBattMilliVolts(),
+; repeater telemetry, and battery.alert remain part of the board/repeater sources below.
 [env:RAK_4631_repeater_lora_ota_no_external_sensors]
 extends = rak4631
 extra_scripts = ${nrf52_lora_ota.extra_scripts}
 build_flags =
   ${rak4631.build_flags}
-  ${nrf52_no_external_sensors.build_flags}
+  ${nrf52_no_external_sensors_keep_gps.build_flags}
   -D DISPLAY_CLASS=SSD1306Display
   -D ADVERT_NAME='"RAK4631 LoRa OTA No Ext Sensors"'
   -D ADVERT_LAT=0.0
@@ -110,7 +111,9 @@ build_src_filter = ${nrf52_lora_ota.build_src_filter}
   +<../examples/simple_repeater>
 lib_deps =
   ${nrf52_lora_ota.lib_deps}
+  ${nrf52_no_external_sensors_keep_gps.lib_deps}
   adafruit/Adafruit SSD1306 @ ^2.5.13
+  sparkfun/SparkFun u-blox GNSS Arduino Library@^2.2.27
 
 [env:RAK_4631_repeater_ethernet]
 extends = rak4631
@@ -158,7 +161,8 @@ build_src_filter = ${rak4631.build_src_filter}
   +<helpers/bridges/RS232Bridge.cpp>
   +<../examples/simple_repeater>
 
-; Explicit lean alternative to the full-sensor, non-OTA Serial1 bridge above.
+; Explicit lean alternative to the full-sensor, non-OTA Serial1 bridge above. GPS remains disabled:
+; both the RAK12501 and this bridge require Serial1, so enabling both would corrupt both protocols.
 [env:RAK_4631_repeater_bridge_rs232_serial1_lora_ota_no_external_sensors]
 extends = rak4631
 build_flags =
@@ -206,12 +210,13 @@ build_src_filter = ${rak4631.build_src_filter}
   +<helpers/bridges/RS232Bridge.cpp>
   +<../examples/simple_repeater>
 
-; Explicit lean alternative to the full-sensor, non-OTA Serial2 bridge above.
+; Explicit lean alternative to the full-sensor, non-OTA Serial2 bridge above. GPS remains available
+; on Serial1 because this bridge owns Serial2.
 [env:RAK_4631_repeater_bridge_rs232_serial2_lora_ota_no_external_sensors]
 extends = rak4631
 build_flags =
   ${rak4631.build_flags}
-  ${nrf52_no_external_sensors.build_flags}
+  ${nrf52_no_external_sensors_keep_gps.build_flags}
   -D DISPLAY_CLASS=SSD1306Display
   -D ADVERT_NAME='"RS232 Bridge"'
   -D ADVERT_LAT=0.0
@@ -227,7 +232,9 @@ build_src_filter = ${rak4631.build_src_filter}
   +<../examples/simple_repeater>
 lib_deps =
   ${nrf52_lora_ota.lib_deps}
+  ${nrf52_no_external_sensors_keep_gps.lib_deps}
   adafruit/Adafruit SSD1306 @ ^2.5.13
+  sparkfun/SparkFun u-blox GNSS Arduino Library@^2.2.27
 
 [env:RAK_4631_room_server]
 extends = rak4631