Nvidia bios modding checksum

Hi! I’m trying to do bios editing for my 3060 ti. I successfully changed the power max power limit in the bios. However, I don’t know how to fix the checksum. Does anyone here knows how to do this? Thank’s in advance!

1 Like

checksum not helps ,.still need bypass certificate “cert2 error”
hwprogramer for modded vbios > skypro +1.8V adapter

or ID and try find compatible vbios on techpowerup :grinning:

Ch31 programer works just fine. I flashed a vbios with it in my rtx 3060ti zotac after a bad update and works fine. How did you modified the vbios? Could you publish the steps and sources? and want to do it thanks!

Hey there! I never succeded to do it but here’s how planned to do it.

Disclaimer: There are risks to consider when flashing and modifying your bios and I am not an expert in this domain. Any damage to your hardware is not my fault.

  1. Get a bios (from gpu-z or something like that)

  2. Get a hex editor (in my case I use HxD)

  3. Now for editing, the bios is written in little endian (meaning a value of AB CD would become CD AB), thus I highly recommend using a dec to hex converter like this one: Binary to Hex Converter. if you scroll down, it shows the value in little-endian.

  4. Now in the editor, search for the power limit value of your bios converted to little-endian. Make sure you are searching for hexadecimal.

To make sure you are editing the right value, you can search for the minimum and target tdp of your bios, as both can be easily obtained. If they are close to the max power limit value, then it should be the right one.

Replace it with the power value you want to be, again in little-endian.

Now, it might now work for every bios, as some are encoded differently.

  1. You need to fix the checksum of the bios. However, I don’t know much about md5/sha256 checksums, so I don’t know how to do it.

-------------- The two following steps might not be necessary, they are only theorical for now -----------

  1. Since we want to flash a bios using a CH341A, we need the file to fit completely the chip size. So you’ll need to find the size of the rom chip on your gpu and add a bunch of zeros so it reaches the correct size. The rom chip might be just the right size thought, so it might no be necessary. (I’m not sure thought I hope someone could confirm this)

  2. You might also need to get a nvidia key and sign the bios, but it might not be necessary, I don’t think anyone has got that far as the time of writing this. Keep a backup of your bios just in case, to not brick your card.

  3. Now you should be good to go to flash your bios. Make sure you have an adapter to the right voltage, you don’t want to fry your rom chip. There might be other things to do, to make it work, but again no one has done it yet, so there’s not really anyway of knowing.

I tried to do this a few years ago with my gt 1030 and never worked.

As far as i know all Nvidia GPUs since Pascal has their VBIOS cryptographically verified by the FALCON and its in HS mode so unless you find a way to downgrade their security or get your modded vbios signed by nvidia i think that even if you flash it successfully with the CH341A programmer the gpu won’t work (black screen) because FALCON will turn off the core if it detects the presence of unsigned code in the firmware.

More info about that:



If you find a way to bypass NVIDIA draconian security measures i highly interested by the way.