trying add a few epub books.. but nothing helped.. reading a few more threads (more than I expected) i stumbled upon this :
https://www.mobileread.com/forums/sho...d.php?t=113346 and it solved.
I have removed SD, booted, and cleaned up all my internal books using the PCLink (they are calibre feed epubs). I will disable them for now.
Damn bug in PB firmware