Alright. So I plugged it, the LED went on for some seconds and then dimmed. I left it for several hours anyway.
Now, it still doesn't register the power button. So no wake-up, no restart, nothing but a dark screen. Laptop doesn't recognize the silly thing, either. I still have it plugged, but seeing there's no LED on, I guess that means it doesn't charge?
So I'm stuck at what to do next. In the Kindle developer's corner, there are some how-to threads that mention 'debrick' and 'black screen'. I am now very worried