That's very frustating. If I only knew I'd never buy this PC.
It's very serions engeneering fault.
I've actiaved PXE settings in BIOS but nothign happens, the PC just is not able to communicate with PXE server.
I hope there is a BIOS fix would be soon but as far as I can see the history of the device has records of serios faults (like lock to 8TDP) and bios updates still do not resolved all problems.
That's another engineering fault from Beelink.
As I already said Beelink's BIOS is faulty.
However, I can provide a tip how to unbrick the device. Some people asked Beelink how to unbrick but look they have got no answer from the last year or maybe even more.
OK. I can do this job instead.
Unscrew 4 screws at the bottom and remove bottom.
On the board you can easily spot a battery connected to the circuit. Unplug the battery from the board and then turn X55 on. CMOS will be reset back to default settings. Then you can turn off your device and plug the battery back to board.
Poor Support, and incompetent.
I made my own research. Beelink doesn't support Legacy BIOS, only UEFI, so I configured PXE server to redirect clients to different bootloaders, depending on their architecture.