Horay - I've brought my little one (n770) back to life
I bought one for circa 30$ - probably some memory issue since It booted to "NOKIA" and there was no possibility to run flasher.
I've exchanged displays and after screen calibration - my cute n770 works like in the old days

To sum up - exchanging whole display - works, there was no malfunction of epson chip in my device.

I've found that I'm able to reflash device successfuly but it doesn't start.
Boots only to Nokia logo, I'll try to test what flasher says in debug mode.