OK, my PB doesn't start again. It's the same behaviour as i had with the 2.0.2 firmware.
I deleted few books (5 maybe) and added one book. Now it's frozen. I'll try reflash firmware but i have to say that i'm really disappointed.
EDIT: So i re-flashed the firmware, PB started, I selected "Maintenance, Clean the state", tried to open the library, device froze again. Well — let's try this once again.
EDIT2: Second reflash. Didn't start. Froze at registration page. Third reflash. Didn't start. Froze at boot logo.
EDIT3: It's like a detective story
Fourth reflash. Now i am able to connect PB to my PC. What should i do next?
EDIT4: I deleted almost whole library (except one book), "db" subfolder in "system" folder, all notes and active content and now it works. Can you make this stable, please? Because now i am worried to add some books.