diff --git a/libraries/AP_HAL_ChibiOS/hwdef/CUAV_GPS/hwdef-bl.dat b/libraries/AP_HAL_ChibiOS/hwdef/CUAV_GPS/hwdef-bl.dat
index 6fdd30d282..52026079e0 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/CUAV_GPS/hwdef-bl.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/CUAV_GPS/hwdef-bl.dat
@@ -43,6 +43,10 @@ STM32_VDD 330U
 # order of UARTs
 UART_ORDER
 
+# use safety button to stay in bootloader
+PB3 STAY_IN_BOOTLOADER INPUT PULLDOWN
+define HAL_STAY_IN_BOOTLOADER_VALUE 1
+
 PB12 LED_BOOTLOADER OUTPUT LOW
 define HAL_LED_ON 1
 
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/CUAV_GPS/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/CUAV_GPS/hwdef.dat
index f456d2e958..77d51beda2 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/CUAV_GPS/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/CUAV_GPS/hwdef.dat
@@ -93,7 +93,7 @@ PB1 SAFE_LED OUTPUT HIGH
 define SAFE_LED_ON 0
 
 # safety button
-PB3 SAFE_BUTTON INPUT
+PB3 SAFE_BUTTON INPUT PULLDOWN
 
 # WS2812 LED
 PB0 TIM3_CH3 TIM3 PWM(1)