diff --git a/ROMFS/px4fmu_common/init.d-posix/rcS b/ROMFS/px4fmu_common/init.d-posix/rcS
index a93f3bd66b..a7e4039ad0 100644
--- a/ROMFS/px4fmu_common/init.d-posix/rcS
+++ b/ROMFS/px4fmu_common/init.d-posix/rcS
@@ -27,6 +27,7 @@ set MIXER                       none
 set MIXER_AUX                   none
 set MIXER_FILE                  none
 set OUTPUT_MODE                 sim
+set EXTRA_MIXER_MODE            none
 set PWM_OUT                     none
 set SDCARD_MIXERS_PATH          etc/mixers
 set USE_IO                      no