Bad news
Kobo sucked, so I decided to get back to Cooler Reader and I followed this post:
https://www.mobileread.com/forums/sho...3&postcount=30
It worked I did something stupied and tried to flash a different combination and bricked the device again: The device starts, shows the kobo logo, 7 black boxed load.
I tried to install original kobo software with kobo-sd-restore-1.8.tgz , but none of my two sd cards, fomated to ext3, is recognized now. Is it possible that I could solve the problem by using a new sd card? Please help!