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
diff --git a/ROMFS/px4fmu_common/init.d/rcS b/ROMFS/px4fmu_common/init.d/rcS
index b1cd919f72..57299d7724 100644
--- a/ROMFS/px4fmu_common/init.d/rcS
+++ b/ROMFS/px4fmu_common/init.d/rcS
@@ -282,7 +282,7 @@ then
 				tone_alarm $TUNE_OUT_ERROR
 			fi
 		fi
-		if [ $OUTPUT_MODE == fmu -o $OUTPUT_MODE = ardrone ]
+		if [ $OUTPUT_MODE == fmu -o $OUTPUT_MODE == ardrone ]
 		then
 			echo "[init] Use FMU as primary output"
 			if fmu mode_$FMU_MODE