I'm so tired of doing firmware research and digging that if i see another ADFU device i'll kill it but not with FW upgrade, better using a HP printer power supply (30V, 400mA).
To recover this mp3 YOU SHOULD HAVE YOUR FIRMWARE BACKUP, IF YOU DON'T HAVE ONE, ASK FOR IT AT "ESTE_URQUIZA [AT] FULLZERO [DOT] COM [DOT] AR", you can write in english, french, spanish, portuguese and italian.
My (brother) player is a FOSTON 512MB, ATJ2051, plays OGG, RGB backlight, etc. It's board is YF00808@163.COM.
First thing to do: Prepare the files, download "693SCL-ORG.bin" from the MP4 firmwares list, its a flash with color LCD controller but it will work for making the player be detected as an unlocked, un-messy GENERIC USB DISK with te keys correctly assigned.
2- prepare your 3535dump.bin, the flashing tools (product tools v1.46) and the USB extension cable.
3- take the player apart and make the short circuit until it gets detected as "USB Device" or ADFU.
You need some specific drivers for this, i don't know where or how to get these drivers working in Win2k/xp, i was very surprised when i saw the ADFU detected on Win2k, i was using Millenium Edition before.
4- flash in ADFU mode with "693SCL-ORG.bin"
5- disconnect the player and wait ten seconds, reconnect it and wait until detected by the computer as "Generic usb disk" or the like, you have to wait, it will take more time than normal, then format it with the HP format tool.
6- Start mp3 upgrade and flash with your DUMP.bin, it can be original or a modified version, make sure it's not the version that killed the player!.
7- Reconnect the mp3 and reformat it. Now it's working like it should.