diff --git a/ROMFS/px4fmu_common/init.d/rcS b/ROMFS/px4fmu_common/init.d/rcS
index 64486fd869..77e5eb303a 100644
--- a/ROMFS/px4fmu_common/init.d/rcS
+++ b/ROMFS/px4fmu_common/init.d/rcS
@@ -643,7 +643,7 @@ then
 			# Exit from nsh to free port for mavlink
 			set EXIT_ON_END yes
 		else
-			set MAVLINK_F "-r 1200"
+			set MAVLINK_F "-r 1200 -f"
 			# Avoid using ttyS1 for MAVLink on FMUv4
 			if ver hwcmp PX4FMU_V4
 			then
@@ -691,15 +691,15 @@ then
 		fi
 		if param compare SYS_COMPANION 921600
 		then
-			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 921600 -m onboard -r 80000 -x
+			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 921600 -m onboard -r 80000 -x -f
 		fi
 		if param compare SYS_COMPANION 57600
 		then
-			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 57600 -m onboard -r 5000 -x
+			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 57600 -m onboard -r 5000 -x -f
 		fi
 		if param compare SYS_COMPANION 460800
 		then
-			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 460800 -m onboard -r 5000 -x
+			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 460800 -m onboard -r 5000 -x -f
 		fi
 		if param compare SYS_COMPANION 157600
 		then
@@ -707,7 +707,7 @@ then
 		fi
 		if param compare SYS_COMPANION 257600
 		then
-			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 57600 -m magic -r 5000 -x
+			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 57600 -m magic -r 5000 -x -f
 		fi
 		if param compare SYS_COMPANION 319200
 		then
@@ -736,7 +736,7 @@ then
 		fi
 		if param compare SYS_COMPANION 1500000
 		then
-			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 1500000 -m onboard -r 10000 -x
+			mavlink start -d ${MAVLINK_COMPANION_DEVICE} -b 1500000 -m onboard -r 10000 -x -f
 		fi
 	fi