repair sunplus mp4 player
 

Hi Guys!I bought an mp4 player which has sony made in japan written on it.
My friend also bought the same one but it had many additional features (wallpaper,gbc emulation etc.) I upgraded my mp4 with my friend's firmware.Everything worked fine except the game emulation.Before upgrading,my Mp4 used to play nes games only.After upgrading my mp4
can recognise nes,gb and bin games but it hangs when i try to play one.
I reset it and tried again but it hanged again.After a few tries,my mp4 comletely blacked out. Now, when i turn it on, it only shows a black screen.
PLEEEEEEZ HELP ME OUT!!!!!!!!!!!!!