Oh, this is really my careless, I didn't back up original firmware before upgrading!
Yes, I tried formatting but ....
I was read from our forum that It need to be disassembled and the chip should be reseted!
But I'm not a careful man, so I'm scared of my operation!
Now, my Mp4 player is still in dead screen with a sand glass!
Please help me in details, thanks arish_06!