gabb9 , the last alternative i can think of is this website here
http://download.impn.net/soft_list/mp3_mp4_firmware/
It seems that they have a list of firmwares, but i'm not sure if the files can be downloaded. Do note that the site is in Chinese, and you might have a problem navigating around.
If it is not under warranty, and you have tried all the v9.xx firmwares and none work, there is pretty much nothing you can do now.