diff --git a/libraries/AP_HAL_ChibiOS/hwdef/FlywooF745/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/FlywooF745/hwdef.dat
index 4527e1e489505..e9a1c84998ac3 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/FlywooF745/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/FlywooF745/hwdef.dat
@@ -162,7 +162,7 @@ define STM32_PWM_USE_ADVANCED TRUE
 
 # FFT option (disabled by default)
 # define HAL_GYROFFT_ENABLED 1
-# define AC_OAPATHPLANNER_ENABLED 0
+# define AP_OAPATHPLANNER_ENABLED 0
 
 # EK2 options (disabled by default)
 # define HAL_NAVEKF2_AVAILABLE 1
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/HEEWING-F405/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/HEEWING-F405/hwdef.dat
index a65b341561e36..139e0d48eef96 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/HEEWING-F405/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/HEEWING-F405/hwdef.dat
@@ -173,7 +173,7 @@ define AP_TRAMP_ENABLED 1
 define HAL_CRSF_TELEM_TEXT_SELECTION_ENABLED 1
 
 # features that users are unlikely to want
-define AC_OAPATHPLANNER_ENABLED 0
+define AP_OAPATHPLANNER_ENABLED 0
 define AC_PRECLAND_ENABLED 0
 define AP_ICENGINE_ENABLED 0
 define AP_OPTICALFLOW_ENABLED 0
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/JHEMCU-GSF405A/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/JHEMCU-GSF405A/hwdef.dat
index 9a5766c43e103..e4b6cafa71c73 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/JHEMCU-GSF405A/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/JHEMCU-GSF405A/hwdef.dat
@@ -159,7 +159,7 @@ define AP_BATT_MONITOR_MAX_INSTANCES 1
 define HAL_PARACHUTE_ENABLED 0
 define HAL_SPRAYER_ENABLED 0
 define HAL_GENERATOR_ENABLED 0
-define AC_OAPATHPLANNER_ENABLED 0
+define AP_OAPATHPLANNER_ENABLED 0
 define AC_PRECLAND_ENABLED 0
 define HAL_BARO_WIND_COMP_ENABLED 0
 define AP_GRIPPER_ENABLED 0
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/SpeedyBeeF405WING/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/SpeedyBeeF405WING/hwdef.dat
index e3f0538e2ab94..7f79fb6e583ac 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/SpeedyBeeF405WING/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/SpeedyBeeF405WING/hwdef.dat
@@ -188,7 +188,7 @@ define AP_ICENGINE_ENABLED 0
 define WINCH_ENABLED 0
 define HAL_ADSB_ENABLED  0
 
-define AC_OAPATHPLANNER_ENABLED 0
+define AP_OAPATHPLANNER_ENABLED 0
 define PRECISION_LANDING 0
 #define HAL_BARO_WIND_COMP_ENABLED 0
 define AP_OPTICALFLOW_ENABLED 0
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/include/minimize_features.inc b/libraries/AP_HAL_ChibiOS/hwdef/include/minimize_features.inc
index faebef7de1f90..4b89cbbb371cc 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/include/minimize_features.inc
+++ b/libraries/AP_HAL_ChibiOS/hwdef/include/minimize_features.inc
@@ -127,7 +127,7 @@ define MODE_FLOWHOLD_ENABLED 0
 define MODE_TURTLE_ENABLED 0
 define MODE_ZIGZAG_ENABLED 0
 define AC_NAV_GUIDED 0
-define AC_OAPATHPLANNER_ENABLED 0
+define AP_OAPATHPLANNER_ENABLED 0
 define MODE_FOLLOW_ENABLED 0
 define MODE_GUIDED_NOGPS_ENABLED 0
 define MODE_SYSTEMID_ENABLED 0
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/include/save_some_flash.inc b/libraries/AP_HAL_ChibiOS/hwdef/include/save_some_flash.inc
index b2720a6449c7a..00294b4d85303 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/include/save_some_flash.inc
+++ b/libraries/AP_HAL_ChibiOS/hwdef/include/save_some_flash.inc
@@ -1,5 +1,5 @@
 # save some flash
-define AC_OAPATHPLANNER_ENABLED 0
+define AP_OAPATHPLANNER_ENABLED 0
 define AC_PRECLAND_ENABLED 0
 define AP_ICENGINE_ENABLED 0
 define AP_OPTICALFLOW_ENABLED 0
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h b/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
index af253acccf772..8eaf28f26b4fe 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
@@ -341,3 +341,7 @@
 #ifndef AP_HAL_CHIBIOS_IN_EXPECTED_DELAY_WHEN_NOT_INITIALISED
 #define AP_HAL_CHIBIOS_IN_EXPECTED_DELAY_WHEN_NOT_INITIALISED 0
 #endif
+
+#ifndef AP_OAPATHPLANNER_ENABLED
+#define AP_OAPATHPLANNER_ENABLED 0
+#endif