Microcode update for i7-3930k (For Patching Spectre)

For awhile now I have been hoping that a patch would come out to deal with the Spectre exploit for my processor. After close to 4 months it’s becoming clear that I might not be-able to patch it using the microcode updates on Intel’s site, or a bio’s update for my motherboard, an Asus X79 Sabertooth. I’m still using Windows 7 SP1 and I would like to stay there if possible.

I see one or two people here have been able to patch the exploit for 3930k, I’ve also been reading the other threads and i’m not 100% sure where I should start, or even what safety precautions I should take before hand.


Here the latest Asus X79 Sabertooth (https://www.asus.com/fr/Motherboards/SAB…pDesk_Download/), the latest stable bios is version 4701.
Be sure that it’s the right motherboard model.
So i modded this bios with latest compatible firmware and latest microcodes against Spectre.
MD5: ED5FA2C3EE776DD4BC954C80E5099E5B
SHA-1: 4483085D45EB7D576C30DE28435C7974176EDFA5


The 7 zip file seems to be password protected. I’m guessing I use the bio’s Update in Asus Suite II like a normal bio’s update once I get it unlocked?

oups password is :


It’s better to use a usb in fat32, access to your bios machine and launch the utility within the bios.

Keep us informed.

Look’s like i’m making some progress. Once I get figured out how to rollback my bio’s to the point where I can start using bin structures again and not cap I should be home free to use the modded bio’s. Disregard that, i’m a idiot.

Ok, so I rename “ASUS MOD X79.bin” to “ASUS MOD X79.rom” and then use “BRenamerl” to make the file into a valid cap file, correct?

Yes with this utility : http://dlcdnet.asus.com/pub/ASUS/misc/ut…5066.1526894774

Here your Bios .cap


Getting closer, I can feel it.


You should rename the bios exactly like the one you’ve already on board if you’ve still have this error message.

Please make sure you’ve have no space between the 9 and the .

Is it possible that my system won’t recognize the modded file because my CPUID is 206D6 and yours is 206D7?

I don’t think so
see here maybe it’s helping you :

MS issued updated KB for Win10 1709

and for 1703

and for 1607

and for RTM

and some time ago - for Win10 1803

@Walls Sorry about the follow up delay, I was out of town for a bit. I was able to get the system to read it as a cap file but now I’m getting “Security Verification Failed”. What I did was use the beta bio’s 4801, and then the spectre patched microcode to make the cap file readable.

@mbk1969 I am not moving to Windows 10 under any circumstances.

@jaken As you wish. I am on Win10 since 1607 and have no issues with my x79 rig. And with latest KB with microcodes I don`t need to bother with BIOS modding to utilize newest microcode.

As I take it you have ASUS motherboard. Use USB flashback feature to flash modded BIOS.

Too bad that you’ve this error message when you try to flash modded bios (maybe ram compatibility or something else), be careful with beta bios it’s a huge risk!!!

I also run a x79 mobo with windows 10 without any issue, i guess jaken use Windows 7 or 8.1 and i think it’s good for him.

That is common for modified Asus BIOS (and other brands sometimes too).

Here is guide on how to flash modified BIOS like these, Asus is first in the list with three methods given
[Guide] How to flash a modded AMI UEFI BIOS

@Walls Error message jaken sees is about wrong checksum of modded BIOS image. UBU tool does change the image but does not calculate new checksum.

@Walls could you upload the cap file one more time?

If bad checksum then don’t flash it, need a new BIOS mod. If you guys need a modification that should flash without bad checksum issue mod with MMTool and insert new microcodes manually, UBU should fix checksum issues but maybe there is a bug.

No matter what, BIOS would still need to be flashed with one of the methods in the above link I posted