Plundervolt "fix" disables undervolting at BIOS level - any way to reverse?

VanGoghComplex

[H]ard|Gawd
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Apr 5, 2016
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New owner of a Dell G7 7700. The laptop's got guts and I really like that it's packing a 2070, but it's a hot mess in need of an undervolt - and apparently that's no longer allowed.

I fired up Intel XTU and the undervolt settings are greyed out. Did some digging and found that Dell (and many other OEMs) are locking voltage modification to mitigate Plundervolt exploits.

As this laptop is a very new model, I don't seem to have the option to roll back to an older BIOS from before the lock. There are only two BIOS available from Dell, and neither of them have voltage tweaks enabled.

I've found some work by enterprising Dell XPS owners in modding their BIOS directly to enable the feature again. It's a single flag that needs flipped from a 1 to a 0, and while it seems a simple thing, I've never done that kind of work to a BIOS and am a bit scared of bricking my machine.

Does anyone have experience with this kind of thing?
 

VanGoghComplex

[H]ard|Gawd
Joined
Apr 5, 2016
Messages
2,031
Managed to do it!

It involved extracting the BIOS file, then extracting a file from that to find the bits that needed flipped.

After that I used a utility called modgrubshell to change those registers and, viola! Undervolting is available again in XTU.

Suck it, Dell. And Intel.
 
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