diff --git a/ROMFS/px4fmu_common/init.d/rcS b/ROMFS/px4fmu_common/init.d/rcS
index a9c5c59ea9..a2e562d6e4 100644
--- a/ROMFS/px4fmu_common/init.d/rcS
+++ b/ROMFS/px4fmu_common/init.d/rcS
@@ -8,7 +8,6 @@
 #
 set MODE autostart
 
-set LOG_FILE /fs/microsd/bootlog.txt
 set RC_FILE /fs/microsd/etc/rc.txt
 set CONFIG_FILE /fs/microsd/etc/config.txt
 set EXTRAS_FILE /fs/microsd/etc/extras.txt
@@ -21,10 +20,12 @@ set TUNE_OUT_ERROR ML<<CP4CP4CP4CP4CP4
 echo "[init] Looking for microSD..."
 if mount -t vfat /dev/mmcsd0 /fs/microsd
 then
+	set LOG_FILE /fs/microsd/bootlog.txt
 	echo "[init] microSD card mounted at /fs/microsd"
 	# Start playing the startup tune
 	tone_alarm start
 else
+	set LOG_FILE /dev/null
 	echo "[init] No microSD card found"
 	# Play SOS
 	tone_alarm error