sercon is only used by APM now

ROMFS/px4fmu_common/init.d/rcS

@@ -42,6 +42,11 @@ then
 	sh /fs/microsd/etc/rc.txt
 fi
 
+# if this is an APM build then there will be a rc.APM script
+# from an EXTERNAL_SCRIPTS build option
+if [ -f /etc/init.d/rc.APM ]
+then
+
 	#
 	# Check for USB host
 	#
@@ -62,10 +67,6 @@ else
 		fi
 	fi
 
-# if this is an APM build then there will be a rc.APM script
-# from an EXTERNAL_SCRIPTS build option
-if [ -f /etc/init.d/rc.APM ]
-then
 	echo Running rc.APM
 	# if APM startup is successful then nsh will exit
 	sh /etc/init.d/rc.APM