[Dead] CS820de - dead after firmwareupdate

[oruoss]

Hello,
I've flashed my CS820DE's firmware to the latest version, but now the machine only boots into this dark waiting screen.
Any suggestions how I can do?

When pressing the buttons 2 + 7 + 8 on Poweron
USB-Recovery
appears on the screen.

Lexmark support offered to repair the printer for €500.

Thanks you for any help.

Regards Oliver