[jaccar]

Hello

Thanks a lot Davidfor

First of all i think that the upgrade that failed was due to the installation of Koreader that i made long time ago

I put the image on the SD card but the writing failed after around 15%; something on my PC prevented to write to the third partition; i rebooted the PC and try again but got the same problem

As the 2 "internal" partition seems ok, i inserted the card in the kobo and it boots correctly and started the upgrade that was alreday downloaded

After that it started and i got the home screen but the screen was locked

I flashed the card again (with the same error) remove the directories of Koreader on the third partition

Started the Kobo again; it boots correctly without reinstalling the update that disappeared from the third partition after the first upgrade

I got the home screen with a message that there are some water on the screen and the screen was locked ...

I tried to clean the screen, force some reset and finally it's started correctly
and all the books and even the statistics were still there (as the third partition was not erased)

I did not yet try to reinstall the upgrade

once again thanks a lot for your help