I've modified your post to include the chip.
Basically your player's chipset is: atj2085 f1152AB
The screen details is: KLM123A01.05.1220
These are the details you need to find a suitable firmware for your player.
Do a serach for your chipset "ATJ2085" on our old archive site here: Search Downloads on MyMPxPlayer.org
See if you can try any one of those to use on your player.
Or you can also search for ATJ2085 on this site here: Search Downloads from MyMPx.org
and see if any of the firmware is compatible with your player.
Unfortunately, it's a trial and error game for you in the hope that you can find the correct firmware.
Let me know how you get on.