diff --git a/ROMFS/px4fmu_common/init.d/rcS b/ROMFS/px4fmu_common/init.d/rcS
index a1105ca2a4..1c04627982 100644
--- a/ROMFS/px4fmu_common/init.d/rcS
+++ b/ROMFS/px4fmu_common/init.d/rcS
@@ -238,6 +238,13 @@ then
 	fi
 	unset MODE
 
+	#
+	# Wipe incompatible settings for boards not having two outputs
+	if ver hwcmp PX4FMU_V4
+	then
+		set MIXER_AUX none
+	fi
+
 	#
 	# Override parameters from user configuration file
 	#