@wass Since all of the boot loaders you mentioned are bios boot loaders and you are seeing the no configuration methods succeeded it sounds like the computer is in bios mode. Its strange that iPXE and bios mode computers are not able to configure the interface. For bios the boot loaders undionly.kpxe or ipxe.kpxe should work on 99.8% of all computers. Does this computer have multiple nic cards?
W