diff --git a/Tools/jMAVSim b/Tools/jMAVSim
index 00bdf6d92b6a8678f5b683a3ebca9e52e88cb5ce..0c25b7c18990a64fc851cfd7fe3aac9a4060aea3 160000
--- a/Tools/jMAVSim
+++ b/Tools/jMAVSim
@@ -1 +1 @@
-Subproject commit 00bdf6d92b6a8678f5b683a3ebca9e52e88cb5ce
+Subproject commit 0c25b7c18990a64fc851cfd7fe3aac9a4060aea3
diff --git a/Tools/jmavsim_run.sh b/Tools/jmavsim_run.sh
index 2eada001d18071ec3d7150587da7abb798cd064c..551351605a15633669ec3d66fb2b68b1a0c32860 100755
--- a/Tools/jmavsim_run.sh
+++ b/Tools/jmavsim_run.sh
@@ -61,11 +61,11 @@ fi
 ant create_run_jar copy_res
 cd out/production
 
-java -XX:GCTimeRatio=20 -Djava.ext.dirs= -jar jmavsim_run.jar $device $extra_args
+java -XX:GCTimeRatio=20 -Djava.ext.dirs= -jar jmavsim_run.jar -lockstep $device $extra_args
 ret=$?
 if [ $ret -ne 0 -a $ret -ne 130 ]; then # 130 is Ctrl-C
 	# if the start of java fails, it's probably because the GC option is not
 	# understood. Try starting without it
-	java -Djava.ext.dirs= -jar jmavsim_run.jar $device $extra_args
+	java -Djava.ext.dirs= -jar jmavsim_run.jar -lockstep $device $extra_args
 fi