diff --git a/ROMFS/px4fmu_common/init.d-posix/rcS b/ROMFS/px4fmu_common/init.d-posix/rcS
index 4d826ddc046..e16c33a1323 100644
--- a/ROMFS/px4fmu_common/init.d-posix/rcS
+++ b/ROMFS/px4fmu_common/init.d-posix/rcS
@@ -186,20 +186,21 @@ param set-default UXRCE_DDS_AG_IP 2130706433 # 127.0.0.1
 
 
 # Adapt timeout parameters if simulation runs faster or slower than realtime.
+# Uses awk for the float multiplication; bc is not installed in all CI containers.
 if [ -n "$PX4_SIM_SPEED_FACTOR" ]; then
-	COM_DL_LOSS_T_LONGER=$(echo "$PX4_SIM_SPEED_FACTOR * 10" | bc)
+	COM_DL_LOSS_T_LONGER=$(awk -v f="$PX4_SIM_SPEED_FACTOR" 'BEGIN{print f * 10}')
 	echo "COM_DL_LOSS_T set to $COM_DL_LOSS_T_LONGER"
 	param set COM_DL_LOSS_T $COM_DL_LOSS_T_LONGER
 
-	COM_RC_LOSS_T_LONGER=$(echo "$PX4_SIM_SPEED_FACTOR * 1.0" | bc)
+	COM_RC_LOSS_T_LONGER=$(awk -v f="$PX4_SIM_SPEED_FACTOR" 'BEGIN{print f * 1.0}')
 	echo "COM_RC_LOSS_T set to $COM_RC_LOSS_T_LONGER"
 	param set COM_RC_LOSS_T $COM_RC_LOSS_T_LONGER
 
-	COM_OF_LOSS_T_LONGER=$(echo "$PX4_SIM_SPEED_FACTOR * 1.0" | bc)
+	COM_OF_LOSS_T_LONGER=$(awk -v f="$PX4_SIM_SPEED_FACTOR" 'BEGIN{print f * 1.0}')
 	echo "COM_OF_LOSS_T set to $COM_OF_LOSS_T_LONGER"
 	param set COM_OF_LOSS_T $COM_OF_LOSS_T_LONGER
 
-	COM_DISARM_PRFLT_LONGER=$(echo "$PX4_SIM_SPEED_FACTOR * 10.0" | bc)
+	COM_DISARM_PRFLT_LONGER=$(awk -v f="$PX4_SIM_SPEED_FACTOR" 'BEGIN{print f * 10.0}')
 	echo "COM_DISARM_PRFLT set to $COM_DISARM_PRFLT_LONGER"
 	param set COM_DISARM_PRFLT $COM_DISARM_PRFLT_LONGER
 fi