Gigabyte MD71-HB0 (also: datto siris 4 enterprise) bifurcation bios mod


Active Member
Jan 11, 2013
A guide.

Gigabyte has chosen not to expose bifurcation capabilities on this board. This board is also found in Datto Siris 4 Enterprise appliances if you scoop them up on ebay or whatever.

Obvious warning that this is not running per the mfr specs anymore if you do this and I will not fix your board if you break it. I have not observed any issues and it's working fine with multiple U.2/M.2 drives per slot a la Supermicro AOC-SLG3-2M2 and Linkreal LRNV94N8.

Prerequisite tools you'll need:
AMIBCP 5.02.0031 from here
EEUpdate from this post
R16 (latest at time of writing) bios image from Gigabyte here

Follow these steps carefully:
1. Use rufus to make a freedos flash drive and put eeupdate on it. Boot the machine in legacy mode and run `eeupdate /all /mac-dump` and take a picture/screenshot of the mac addresses
2. With the machine off and unplugged, use a flash programmer such as flashcat to save a copy of the existing firmware (in case things go badly).
3. Modify the BIOS image you downloaded from Gigabyte using AMIBCP as shown in the attached image and save a copy
4. Flash the modified bios image with the flash programmer
5. Boot freedos again and use eeupdate to program the mac addresses you recorded earlier. The syntax is `eeupdate /nic=# /mac=AABBCCEEFF00`
6. If all is well, the BIOS will have IOU bridge options in the IIO menu now. You have to disable auto detect. It doesn't work. Below is the list of Sockets and IOUs for each slot. Just set them to x4x4x4x4 if you want to bifurcate
From my notes:
Slot 6 = Socket 1, IOU1
Slot 5 = Socket 1, IOU0
Slot 4 = Socket 1, IOU2
Slot 3 = Socket 0, IOU2
Slot 2 = doesn't work
Slot 1 = doesn't work

If anyone has any improvements to suggest or know how to get Slot 2 and Slot 1 to work, let me know! I'm doubtful on Slot 1 ever working because I believe it goes through the PCH. I'm fairly sure you will have to use a flash programmer as earlier attempts out of boredom to do this last year flashing by IPMI rejected modified images (signing issues, probably)

At some point, I'll try this on Gigabyte MD70-HB0 (also: datto siris 3 enterprise) and report back whenever I get around to it. It should work there as well.


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