diff --git a/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py b/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
index 6a52959cee..b59f3e06aa 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
+++ b/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
@@ -2568,8 +2568,12 @@ def add_apperiph_defaults(f):
 #ifndef HAL_WATCHDOG_ENABLED_DEFAULT
 #define HAL_WATCHDOG_ENABLED_DEFAULT true
 #endif
+
+#ifndef AP_FETTEC_ONEWIRE_ENABLED
+#define AP_FETTEC_ONEWIRE_ENABLED 0
+#endif
 ''')
-            
+
 
 # process input file
 for fname in args.hwdef: