diff --git a/ROMFS/px4fmu_common/init.d/rc.interface b/ROMFS/px4fmu_common/init.d/rc.interface
index afe71460de..7f793b2198 100644
--- a/ROMFS/px4fmu_common/init.d/rc.interface
+++ b/ROMFS/px4fmu_common/init.d/rc.interface
@@ -3,7 +3,7 @@
 # Script to configure control interface
 #
 
-if [ $MIXER != none -a $MIXER != skip]
+if [ $MIXER != none -a $MIXER != skip ]
 then
 	#
 	# Load mixer