A brief follow-up
My KT miraculously returned to life! After spending a night completely stoned (2 black squares, the other white), he resurrected this morning after a difficult start (yes, the power button has work this time...

)
How long will this last? (strangely, it reminds me my first steps with Ubuntu

).
To all those who have problems with their KT, I want to say that God exists and takes care for Kobo, and you certainly must have faith to use these eReaders.
Now I have to wait another down and pray that it is not soon.