On Sun, 03 Feb 2013 15:20:09 +0100 Melchior FRANZ mfranz@aon.at wrote:
I compared my previous BIOS memory contents with the original version 0705, and there are four areas that differ. All memory in the ASUS file has 0xff set throughout, where mine had data.
(1) 000c17-00bd8c (45430 Bytes; custom settings like storage devices) (2) 00fef0-00ffef (256 Bytes; ???) (3) 014008-014052 (74 Bytes; contains former serial number and MAC) (4) 37c664-37c691 (45 Bytes; contains former serial number)
Overwriting these areas with 0xff doesn't seem to have done any harm. The MAC address was in 1404d-14052 -- it's no longer there after flashing BIOS 1605, but ifconfig still knows it, so I assume it's also stored in the ethernet hardware.
yes, probably in an eeprom (which costs money and hence is often left out... not on expensive server boards, but cheap consumer ones...). interesting that they store it nevertheless in the flash too. maybe there is a (hidden) bios option to spoof the mac... i had a DFI board once that had that.
I don't find the new "serial number" 1234567890 in the new 1605 BIOS, nor in the current BIOS dump (neither little/big endian hex, nor ascii).
it is probably written by the bios algorithmically, or it may be compressed. but TBH i do know very little about firmware formats. so just to make this clear: that's all speculation, or educated guesses at best :)