@throsu,
It's a very frustrating "job" to switch the kobo back on when it's locked like that, I'm never patient enough and I always give up thinking that it's broken because it's so illogic that a reset pin don't reset !
Pressing a stupid pin, seeing nothing happening during half an hour is so frustrating and you feel like you're spending your time doing the most stupid thing on earth
If your problem is like mine, it could work... Good luck.