[flashrom] Mysterious MAC-Address Changes after BIOS-Upgrade with flashrom

[Peter Daum]

--- David Hendricks <dhendrix at google.com> schrieb am Mi, 24.11.2010:

> The "00:19:66:97:d7:e2" you're seeing can be encoded in numerous ways and
> probably omits the ':' character. It may also be in a compressed portion
> of the image.

... actually, I already know the position, where the bios stores the MAC address. Unfortunately, it does not work to just change the address in the bios image and write the changed image back:
- In the image file that is provided by the vendor, these bytes
  just contain ff:ff:ff:ff:ff:ff (without ":")
- When I flash the bios using the AMI tool, reboot and then compare
  the actual bios contents with the file, those bytes have been overwritten
  with the machine's MAC address (+ many other changes)
- When I flash the same image using flashroom, the MAC address is sometimes
  unchanged, sometimes changed to 00:19:66:97:d7:e2; in any case, the
  corresponding position in the bios also contains the MAC address again.
- My attempts to change the MAC address on file and then flash it always
  ended with "00:19:66:97:d7:e2", no matter which address I used
- When I take a complete bios image from another machine and flash it,
  the machine gets the MAC address from the machine the bios image
  originally came from