When I get home, I can send you my backuped files (minus the example ebooks). Maybe it just needs the system and font files and those will be compatible with your version.
About being impossible to downgrade firmware, I guess we should have seen that coming. Of course Bookeen wouldn't make it easy to make their ePub version able to read mobipocket files (even if the user decided to dismiss ePub compatibility).
But it's a slopy work there, leaving the manual and example books in mobi format, when the device can only read ePub.
