diff --git a/libraries/AP_HAL_ChibiOS/hwdef/CubePilot-CANMod/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/CubePilot-CANMod/hwdef.dat
index 924a4629513f4..4637d12cc777c 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/CubePilot-CANMod/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/CubePilot-CANMod/hwdef.dat
@@ -8,8 +8,6 @@ MCU STM32H7xx STM32H757xx
 define CORE_CM7
 define SMPS_PWR
 
-define HAL_BUILD_AP_PERIPH
-
 # board ID for firmware load
 APJ_BOARD_ID 1079
 
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F412/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F412/hwdef.dat
index 90dab1d604629..57a1c2684f91d 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F412/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F412/hwdef.dat
@@ -97,7 +97,6 @@ PA12 CAN1_TX CAN1
 define HAL_CAN_DEFAULT_NODE_ID 0
 
 define HAL_NO_MONITOR_THREAD
-define HAL_BUILD_AP_PERIPH
 define HAL_DEVICE_THREAD_STACK 768
 
 # disable dual GPS and GPS blending to save flash space
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F9P/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F9P/hwdef.dat
index e18eeb4aedaa1..042a8a0a0974d 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F9P/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F9P/hwdef.dat
@@ -106,7 +106,6 @@ PB9 CAN1_TX CAN1
 PC1 GPIO_CAN1_SILENT OUTPUT PUSHPULL SPEED_LOW LOW
 
 define HAL_NO_MONITOR_THREAD
-define HAL_BUILD_AP_PERIPH
 define HAL_DEVICE_THREAD_STACK 768
 
 # we setup a small defaults.parm
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/kha_eth/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/kha_eth/hwdef.dat
index 6eb9809316ce0..373df3048c488 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/kha_eth/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/kha_eth/hwdef.dat
@@ -20,8 +20,6 @@ FLASH_SIZE_KB 2048
 # setup build for a peripheral firmware
 env AP_PERIPH 1
 
-define HAL_BUILD_AP_PERIPH
-
 # bootloader is installed at zero offset
 FLASH_RESERVE_START_KB 128
 FLASH_BOOTLOADER_LOAD_KB 128