diff --git a/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py b/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
index a7e2e37a8b..bc90ab3f40 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
+++ b/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
@@ -3322,6 +3322,14 @@ INCLUDE common.ld
 #define AP_BOOTLOADER_ALWAYS_ERASE 1
 #endif
 
+#ifndef GPS_MOVING_BASELINE
+#define GPS_MOVING_BASELINE 0
+#endif
+
+#ifndef AP_UART_MONITOR_ENABLED
+#define AP_UART_MONITOR_ENABLED AP_GPS_ENABLED && (GPS_MOVING_BASELINE || BOARD_FLASH_SIZE>=256)
+#endif
+
 // end AP_Periph defaults
 ''')