diff --git a/src/drivers/px4flow/px4flow.cpp b/src/drivers/px4flow/px4flow.cpp
index 64f1865f23..04aa31b852 100644
--- a/src/drivers/px4flow/px4flow.cpp
+++ b/src/drivers/px4flow/px4flow.cpp
@@ -778,6 +778,9 @@ start(int argc, char *argv[])
 #ifdef PX4_I2C_BUS_EXPANSION1
 			PX4_I2C_BUS_EXPANSION1,
 #endif
+#ifdef PX4_I2C_BUS_EXPANSION2
+			PX4_I2C_BUS_EXPANSION2,
+#endif
 
 			-1
 		};