You can certainly flash more systems with Linux and flashrom than you might think. But compared to BIOS builtin or DOS flash tools no config data is kept. The most part is not that critical, but for example new asus systems use insyde uefi versions that store the mac adress there. If you know what you do you can use ethtool to restore the mac adress you want. But the general user should prefer using the official flash tools. For backup purpose flashrom however is great, it even stores the current settings of those uefi systems if you like that. More users should test it and report back to flashrom, the current default way to access the eeprom seems to be SPI and i think much more boards than the listed ones would work with it. If you have got a backup you can run to easyly identify raw parts with config settings. Also you can check 6 byts at 1000h offset for the mac adress of your first nic... I am definitely a fan of flashrom, i used it with older systems a lot to flash modified roms - added via raid rom, gpxe or ipxe rom instead of pxe rom, plop instead of pxe. i also flashed a 3com nic with ipxe and plop (you have to disable onboard nic but enable lan boot). It is a really great tool.