grubmod

By default, BIOS/UEFI only shows users a small part of its variables (settings). Most of them are hidden, and the standard interface doesn’t display them. These hidden options control everything — from memory timings to CPU power parameters.
BIOS/UEFI variables are key–value pairs stored in non-volatile memory (NVRAM). Manufacturers usually lock access to these variables.

grubmod is a tool that allows you to view and modify hidden BIOS variables directly through the GRUB bootloader using a convenient graphical interface.
It automatically generates a valid script with the desired changes and applies it following the given instructions.

Disclaimer

The author is not responsible for any possible damage caused to hardware as a result of using this project.
You use this program at your own risk.

Known Issues

• As far as known, it doesn’t work on AMD systems.
• Some parameters don’t have all possible values.

Features

• Displays all BIOS/UEFI variables, including hidden ones, along with their data.
• Convenient filters for viewing and analyzing parameters.
• Modify variables and apply changes through GRUB.
• Import and export configs.
• Built-in presets with various configurations.
• Script generation and execution for automating changes.
• Error tracking via logging.

Usage

1. Preparing working files

1. Download the latest release of grubmod.
2. Download the current version of your BIOS firmware and place it in your working folder.
3. Open the firmware file in UEFIToolNE in the files folder.
4. In the window that opens, press Ctrl + F.
5. Select the Text section and type any parameter name, for example: ASPM.

6. After the search, go to the Setup/PE32 image section entry.
7. Right-click the PE32 image section in the Setup section.
8. Select Extract as is.

9. Save the file in files folder.
10. Open CLI in the files folder, and insert the command:

ifrextractor.exe "extracted_file_name.sct"

11. Open the saved file in grubmod using the Import file button.

---

3. Preparing the USB drive

1. Format your USB drive as FAT32.
2. Download a UEFI shell file from one of these sources:
   • UEFI-Shell (shellx64.efi)
   • Official EDK2 stable releases (ShellBinPkg > UefiShell > X64 > Shell.efi) — may be outdated, not recommended.
3. Rename the downloaded UEFI file to BOOTX64.EFI and place it at: USB:\EFI\BOOT
4. Place setup_var.efi and setupvar-script.nsh in the root of the USB drive.

4. Script execution

1. Boot from the USB drive via your motherboard’s boot menu (check your model’s key combo online).
2. In the UEFI shell, identify your USB drive:
   • Check the displayed Mapping Table (to re-display it, type map). Most likely, it’ll be FS0.
3. Run the script with:

   .\setupvar-script.nsh

4. Wait until the script finishes execution.
5. Power off your PC using the physical power button to apply the changes.

---

Config Syntax

If you want to create/load a custom config, follow this syntax:
If a parameter is missing or incorrect, it will be ignored.

PARAMETER NAME | DESIRED VALUE

If you want a max value:

PARAMETER NAME | Max

The config file must have a .txt extension, and the filename must contain the word config.
Examples: my-config.txt, Configtest.txt.

Keyboard shortcuts

Enter     - Search
Ctrl + C  - Clear
Ctrl + G  - Google
Ctrl + E  - Export script
Ctrl + L  - Load config

Credits

• UEFI-Editor by BoringBoredom
• grub-mod-setup_var by datasone
• setup_var.efi
• UEFI

Troubleshooting & Support

If you encounter errors or bugs, please report them via the issue tracker.
Sometimes, after changing BIOS parameters, the system might not boot. To reset BIOS to defaults, clear the CMOS or remove the battery.