Supported Models

• XPS

  • 7590

• Vostro

  • 5471 (https://github.com/Lyceris-chan)

Most likely any model that has a K series skew CPU

If you are able to make it work on a model not already listed please create a issue with your devices model

Dell unlock Undervolting

A guide to unlock voltage control on Dell laptops above BIOS version 1.6.1, Undervoltiong was locked away to prevent the Intel plundervolt vulnerability (CVE-2019-11157)

Disclaimer

If you follow the instructions correctly there is little chance of bricking your laptop. I will not take responsibility if you brick your laptop. (Note: You can clear CMOS by holding the power button for 30s on XPS laptops)

Requirements

• Universal IRFE Extractor Link
• Dell PFS Extract Link
• UEFITool Link
• The latest BIOS installer for your laptop
• modGrubShell EFI Link

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Step 1. Extracting the BIOS from the installer

• Copy the Dell BIOS update tool to the directory containing Dell PFS Extract
• Open CMD and cd to the directory containing Dell PFS Extract
• Enter this into CMD "Dell_PFS_Extract.exe (Directory to the Dell BIOS update exe)" (Note: if the directory contains spaces add quotes around it (ex."C:/Dir/Thank you dell/")
• A new folder will appear in the Dell PFD Extract directory containing your extracted BIOS

Step 2. Finding the Overclocking lock (CPU Voltage lock) Address

• Open UEFITool click file, open new image file. Navigate to the new folder created in the Dell PFD Extract directory, select System BIOS with BIOS guard and click open.

• Hit CRTL+F and switch to text search. Type Overclocking Lock and hit enter. UEFITool should show "Unicode Text Overclocking Lock in setup/PE32..." Double click on this entry.

• Right click on the entry UEFITool brings you to. Click extract as is. Step 3. Universal IRFE Extractor

• Open Universal IRFE Extractor and navigate to the file you extracted from the previous step open this, click extract.

• Open the text document that Universal IFR Extractor returned. Search for Overclocking Lock

• Copy down the variable mentioned beside "Overclocking Lock". In my case "0x789" Step 4. Unlocking voltage control

• Format a USB to FAT32

• Make a folder called "EFI" and within that a folder called "BOOT"

• Rename modGRUBShell.efi to bootx64.efi and place it in "BOOT"

• Boot to this usb and enter "setup_var_3 "variable you got earlier" 0x00 (In my case "setup_var_3 0x789 0x00")

• Some laptops require manaul boot device entry to appear in the boot list

• Type "halt" and unplug the USB and reboot your computer