Can\'t Find MAC Address in BIOS.rom file

Hey, i’ve been trying to find my MAC address in my BIOS for hours now and can’t. Linked below is my BIOS dump.

Per TMAC and the wimc get MAC, my MAC address is 2C-F0-5D-74-E7-0A. I’ve tried to search the linked BIOS DUMP with HxD and have not been able to find my MAC address. I’ve also searched for the MAC vendors used by Micro-Star and while I can find those, changing those causes my BIOS to be unbootable.

I’ve heard UEFITool can help but am unsure how to use it.

My motherboard is a MSI B550-A-PRO and I am on bios update: 7C56vA4

Any and all help would be appreciated! I’ve been going at this problem for days with no solution so far.

Edit: I want to find the MAC address because I want to change it (using Hex editor) at the BIOS level.

Edit2: Here is a fresh bios dump compressed with winrar.


You can’t change MAC ID at BIOS or chip level, well you can, but then it wont function. By Law, each LAN item can only function with MAC ID given to it at the factory.
So you can change it to fix it, for example if you lost it during some incorrect BIOS flash and it was wiped/replaced to all FF FF or 88:88:88:87:88 for example
In such cases you can put it back to proper MAC ID, but you can’t just put in some new one. For sometime like that you have to use a MAC spoofer
The only other way to change actual LAN MAC ID and have it be functional is to replace the chip directly.

For this system, MAC ID is not stored in BIOS, thus would be stored in chip FW only.
You can change it there with any MAC Writing software compatible with your LAN chip ID, but if you change it to other than original then Ethernet will not function

Is this true for all bios? Or just MSI ones? I’ve read a guide where someone dumping their ASUS bios using AFUWIN and then opening the dumped bios with Hex editor and searching for their MAC address and changing it. He was able to later flash that same bios using AFUDOS.

This is true for ALL boards, about the changing of LAN MAC ID. But, this is ONLY true about LAN MAC ID not being in this particular boards BIOS, some MSI (And others) BIOS do store MAC ID, just this one does not.
Yes, many Asus boards BIOS contain MAC ID and without it, or with it being incorrect/non-original, LAN will not function. So what you read was only about correcting the MAC ID back to original, not about them using some newly created one, otherwise they were lying (it’s not a possible thing to do)
AFU, or being able to flash in BIOS or not, is not relevant to any of this

Great! Thank you for the help! The person in the guide never shows their new MAC address anyway, so I guess maybe they were mistaken!

I really appreciate the help a lot, i’ve been racking my head trying to figure this out for so many hours haha

@JustWannaChangeMac - Yes, plus they are possibly changing it in informational areas anyway (DMI info, NVRAM etc) and that would not affect functionality.
It also would not defeat the software your avoiding, unless it’s dumb and does not look at actual functional/in-use MAC ID. Or, he may not be being honest too.
You can spoof MAC ID, but you can’t simply change it and it functions, otherwise spoofing of a MAC ID would never have been invented as “a thing” because it would never be needed and anyone could simply change their MAC ID’s all day long.

Your MAC ID is stored in the LAN Chip FW, you can wipe or change it, but then you wont have LAN functionality
Here, you can spoof this way, but I suspect it wont pass what your trying to avoid -…-linux-and-mac/
or you can use TMAC software

This may work for RTL8111, I’m not sure

But, as mentioned, see here, MAC ID that will function, is burned into a fuse and cannot be changed (and have device function after that, until changed back to correct one)…et-card/4377/12

Here, using this package and the RTL811 files (specifically PG8168 + CFG file - put on DOS Bootable), you can change your MAC ID in FW, but if you want it to work after that you will have to change it back to the correct one
Be sure to check out all the stuff in RTL811 folder first, not just the PG8168 folder that is separate

All can be done without cfg file I think, just run PG8168.EXE /? to see help/function info…184506233548067

Im somewhat confused. I’d like to try to change my MAC ID to a non-functional one, as long as I would be able to revert it.

So Im going to set up my bootable DOS drive with FreeDOS. Then I place the PG8168 file in the main directory and copy the CFG as well. Then I boot up the drive. What commands should I use inside the FreeDOS to change the MAC address. And what would I change the MAC Address too? Are their options or does it just choose something like 0000000

And then how would I revert it? Just by flashing a backup bios?

Sorry if these are stupid questions, I’m very new to bios mods and some of this stuff is hard for me.

Picture of what my drive looks like

EDIT - What do I press at this screen? Here

Yes, that’s why I gave you all that info, I assumed you’d want to test making it non-functional and wasn’t going to believe it until you could
CMAC?? Sorry, I know nothing about that. Use PG8168.EXE /? in CMD prompt as mentioned to see commands used to change MAC ID. You can do this from DOS or XP
Set whatever you want, then once you are done testing do the same over again to put back in correct ID and make your LAN Work again

Example -
PG8168.EXE /r << Readout EEPROM or EFuse content to standard output - This will create a CFG file
PG8168.EXE /vMAC - Display SVID, SDID, and MACID
PG8168.EXE /w << WRITE EEPROM or EFuse per the CFG file (this is default action) - I suggest not using CFG file, unless you first dump it, then edit only the MAC

This is not a mod BIOS, and you are not touching the BIOS at all. So no, flashing BIOS would not do anything here, once you change it the only way to change it back is by using same process and putting back in the correct MAC ID.
My advice to you about all this, is to leave it alone, disable Ethernet in the BIOS, and purchase an add-in LAN Card to use when you need to game with other than original MAC ID.
When you don’t want to use it, you can then disable in device manager, or unplug the Ethernet cable from the card.

* Edit - At the “Screen” you asked about, you keep hitting enter until you’re done being shown all the info/commands/examples

Gotcha, i disabled the lan card in windows, does that mean the game will not be able to scan for the original MAC address as I am now using an add in lan card.

When i put in the command PG8168 /r it states - No RTL8168/RTL8111 FAMILY CARD FOUND

So if i cant find the card in this setting, the game will be unable to as well, correct?

Also, to have a MAC address, do you need to be connected to the internet?

Not sure, probably still could detect it, I would disable in BIOS.
This software is for that LAN CHIP ID you gave me, so it should find it?
No, MAC ID is there/visible to anything looking, without internet connected, provided LAN chip is enabled and board is running.

Thank you for everything! I cant express how helpful you have been!!!

I had the same issue. You can add a custome MAC in windows LAN device settings.