diff --git a/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py b/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
index 60db0d1837..a8351e0242 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
+++ b/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
@@ -3123,6 +3123,14 @@ INCLUDE common.ld
 
 #define HAL_CRSF_TELEM_ENABLED 0
 
+#ifndef AP_SERVORELAYEVENTS_ENABLED
+#define AP_SERVORELAYEVENTS_ENABLED 0
+#endif
+
+#ifndef AP_RELAY_ENABLED
+#define AP_RELAY_ENABLED 0
+#endif
+
 /*
  * GPS Backends - we selectively turn backends on.
  *   Note also that f103-GPS explicitly disables some of these backends.