HP EliteBook 840 g5

BIOS/UEFI Modding BIOS Modding Requests
1

I have a hp EliteBook 840 G5 laptop (released in 2018) for 8 months now I have been trying to figure out how I can unlock undervolting which was locked with a patch from intel in 2019 and I was advised to consult people on this forum. I can’t get the bios file from the system so I used the one provided by HP official site. I found where the overclocking lock value file is located using UEFITool in my case was named “OC” then I used IRFExtractor to be able to read it but the protocol was unknown then I gave up on this method and tried others which again ended in failure there is no point in explaining about each attempt separately. If anyone knows the value of overclocking lock or have already modded bios I would appreciate it!

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Thanks for reading! This is my first post I have no idea how the site works.

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2

I reply because you messaged me. I wouldn’t do this otherwise because I consider your request as a hopeless quest.

The only patch Intel could provide is either microcode or ME software update. These have nothing to do with the overclocking lock value. If Intel wants Oc-ing being locked, you cant change it by editing variables.

If you’d want to revert the patch… here’s why you cant do so.
HP laptops are notorious for firmware protection. This means you cant install an edited bios without special equipment, or run it without breaking the protection.

In case you’re looking how to use IFRExtractor to extract HII data, you should find/extract drivers which match the following pattern: “00020EA7”.

These are supported by IFRE

Hex pattern "00020ea7" found as "00020EA7" in HpSetup/PE32 image section at body-offset 109BB6h
Hex pattern "00020ea7" found as "00020EA7" in HpSetup/PE32 image section at body-offset 10B836h
Hex pattern "00020ea7" found as "00020EA7" in HpSetup/PE32 image section at body-offset 10DE26h
Hex pattern "00020ea7" found as "00020EA7" in HpSetup/PE32 image section at body-offset 112CB6h
Hex pattern "00020ea7" found as "00020EA7" in UiThirdPartyApp/PE32 image section at body-offset C0B6h
Hex pattern "00020ea7" found as "00020EA7" in UiThirdPartyApp/PE32 image section at body-offset C2F6h
Hex pattern "00020ea7" found as "00020EA7" in Ip4Dxe/PE32 image section at body-offset E3B6h
Hex pattern "00020ea7" found as "00020EA7" in Ip6Dxe/PE32 image section at body-offset 14EB6h
Hex pattern "00020ea7" found as "00020EA7" in VlanConfigDxe/PE32 image section at body-offset 7706h

But you won’t find these drivers in the original bios when opened in UEFITool. :stuck_out_tongue:
You need to edit bios file a bit, so the unknown type volume with GUID 372B56DF-CC9F-4817-AB97-0A10A92CEAA5…

gives a new FFSv3 volume with DXE drivers

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image639×677 26 KB

3

Thanks for the reply!:sweat_smile:

“You need to edit bios file a bit” Can I use HxD, ghidra to edit it or other programs and how exactly to make the whole process.

4
HxD, bios 012901

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Edited file is on the left.

5

Can this be used to unlock the BIOS rollback to the version where these things are not locked and how exactly to reverse engineer it?

6

How? No, this edit is just for UEFITool to read file better.

Also, I have no idea how to allow rollback.

7

Thanks for the help if you cant help me idk who can xD! This laptop is cooked I dont think overclocking will be possible to unlock.