thanks cory tooooo much,he make a very useful MK5 2M save memory test App,just run it then can check your save memory working perfect or not!
how to use:
[1] when you run it first time,just click it and start to excute the self-test and give out the testing report. If it's passed,then turn off your NDS.
[2] re-power on your nds and run this App again,it will verify the memory data automatical, if pass too,then mean your MK5 save system is working perfect and can keep the data after power off,100% QC pass.