Help me identify this - cannot play ANY other game on it...

Well, i got this MP5, to which i would love to install and play other games, besides the original one:

CPU: atj2259c (zd92kbb cbc)
Board ID: MP680A/B ver1.0
Flash: Powerflash asu1ga30ht-g25ca
RAM: etrontech em639165ts-6g
LCD: FPC4304006 (4.3-inch display screen )
CAM: RA357DG
Firmware: int_us225a_121203a


You can see a video of it here: youtu.be/q7h_x5kPl6Q


My goal is to be able to run/play some additional games, besides that one which comes with this chinese MP5 player. All games placed in the SD card, do not work at all.



Notes:

• This device is working and it comes with a game called "Auto X.gba", which was made by JungleTac ( bootleggames.wikia.com/wiki/JungleTac ).
  

• Besides that game and after placing other .gba games in the SD card, they aren't being recognized...nothing happens when i execute them.
  

• Do note that i've tried other kind of platform games like .nes and the same thing happens...meaning, nothing.
  

Anyway, figuring out a compatible firmware for this device would be a huge step forward. So, can ANYONE help me out with this?


Thank you for your help