ETMegabyte 1246311010|%e %b %Y, %H:%M %Z|agohover
In the course of testing, we found that the bootloader contains the MAC address of your NIC. If you rescue your MBWE or MBWE2, then you will end up wtih the MAC of 00:90:A9:15:99:84. THis is not a problem unless you have more than one rescued MBWE on your network. There is finally a solution!!!
In another thread, Allexxx and I talked back and forth about this problem. It was found that not only is your MAC contained inside the boot loader, but that there's a checksum in there as well, so you can't just use a hex editor to change the mac address stored there. You also have to change the checksum bytes (4 characters)… Fortunately, Allexxx was able to put together a script thingy that will calculate the proper checksum for any mac address. However, it's installation and usage requires linux knowledge. I have installed it on my linux machine here, and it works. For those without linux knowledge, or are unable to do it yourself, I'm willing to run it here and let you know what the proper checksum for your mac is…
If you issue the following command:
dd if=/dev/sda of=/root/fullbootloader.sda bs=512 count=10796
It will extract the entire boot loader from your MBWE or the first drive of your MBWE2.
If you open it using a hex editor, you will find your mac address hardcoded at address 0x5F90. It will show as ++++++,0x++++, with the +'s being hex numbers. The rescue images available here have 0090a915,0x9984, which correspond to mac address 00:90:A9:15:99:84.
However, the checksum for that MAC address is stored at address 0x5E00 (the 4 characters before the word "bootcmd"). In the rescue images, the checksum is BF C6 3D 52.
To properly change your mac address, you will need to change both of these. Below is a table of the known public mac addresses and their corresponding checksums. If you would like the proper checksum of YOUR MAC, PM me, and I will edit this list to include your MAC and it's proper checksum…
Once you change the mac address and checksum in your boot loader file (the file you made with the command above), you can restore it using the following command: (note that the boot sectors of the 2 drive MBWE2's are identical, so you can issue the following comand twice, and substitute /dev/sda with /dev/sdb for the second command)
dd if=fullbootloader.sda of=/dev/sda bs=512 count=10796
So, now to the list of mac addresses that have been posted to this board, and their proper checksums
MAC Address Checksum Bytes Source
00:90:A9:15:99:84 BF C6 3D 52 Christoff4444's Rescue Images
00:90:A9:78:32:D1 A4 90 E8 43 Allexxx's HOWTO for changing MAC addresses
00:90:A9:25:78:28 C5 A9 56 35 Shemers MAC (from another thread on this board)
00:90:89:45:41:B3 2B 49 0E 2A Jharris1993 MAC (from another thread - and yes, it's 89, not A9 in the MAC)
00:90:A9:45:CC:12 49 B8 E2 AE boudzz MAC (From a kernel log in another thread)
Again, if people PM me with their MACs, I will update this thread with their checksums…
-ET
ps. If you make a copy of your bootloader, and then edit it for your mac address, keep it around somewhere in a safe place in case you need to rescue your MBWE or MBWE2 again in the future… It will just make things easier…
