In your first post you wrote that you have a board ID:MP3-910255 VER.3.0 and chip ATJ 2091N same as mine.

I have been "reading" my backuped firmware and it seems to be corrupted (no hardware problem) and that could be caused by one of the reasons mentioned here

As you mention when you connect your player to your pc it does not recognize the player as a drive. That is also my case, but when I load "FW 9.1.51_ATJ2091N SAMSUNG 2024MB-FM.bin" the 2GB drive is shown in the folder "Computer" and I can read and play the files inside, but I can either format nor delete or write any files on it. Other parts (Display, buttons, etc.) also don´t work.

You mention you have a communication problem between tool and chip. It is also my case. Tools like: s1fwx, mp3 player tools, mp3 player update tool do not recognize my device (message: the device is not connected) The only way I could write FW was using the tool s1clone and the above mentioned binary file renaming it fom .bin to .s1clone file.

A last question: Is your mp3 player still on the 1 or 2 years guarantee period?