diff --git a/src/drivers/boards/aerofc-v1/board_config.h b/src/drivers/boards/aerofc-v1/board_config.h
index 416b79ea92..1d1e958d56 100644
--- a/src/drivers/boards/aerofc-v1/board_config.h
+++ b/src/drivers/boards/aerofc-v1/board_config.h
@@ -78,7 +78,8 @@
  *
  */
 
-#define PX4_I2C_BUS_EXPANSION	1
+#define PX4_I2C_BUS_EXPANSION   1
+#define PX4_I2C_BUS_EXPANSION1  2
 #define PX4_I2C_BUS_ONBOARD	3
 
 #define PX4_I2C_OBDEV_HMC5883	0x1e