[nhedgehog]

Just to clear things up a little bit:
On pocketbooks the internal memory is divided into different parts, most is not available to the user (without root) but there is a section of the device that is available to users. Internally it is mounted as /ext1/ and it is fat32 formated.
Some files such us keyboard files and setting files as the aformentioned extensions.cfg are located in the not accessable part of the file system BUT if a file with the same name is put in a corresponding folder on the accessable partition, this is used instead of the hidden files. So if you delete your extension.cfg, the hidden extension.cfg will be activated and everything is working as before. That gives us the option the reset the device by formatting the accessable partion and afterwards force install an update (Buttons Power&Left&Right pressed simultanously during boot).