diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32f47_mcuconf.h b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32f47_mcuconf.h
index e3627924d9..41cab6f73f 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32f47_mcuconf.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32f47_mcuconf.h
@@ -128,8 +128,12 @@
 /*
  * CAN driver system settings.
  */
+#ifndef STM32_CAN_USE_CAN1
 #define STM32_CAN_USE_CAN1                  FALSE
+#endif
+#ifndef STM32_CAN_USE_CAN2
 #define STM32_CAN_USE_CAN2                  FALSE
+#endif
 #define STM32_CAN_CAN1_IRQ_PRIORITY         11
 #define STM32_CAN_CAN2_IRQ_PRIORITY         11