jrd / grub2-hackbgrt

Change BGRT at grub 2 boot level

Hackbgrt for GRUB 2

Inspired by the work of HackBGRT EFI application.

This module is for GRUB2 (x86 32 or 64 bits) and allow to modify the EFI BGRT at grub level.

The BGRT stands for Boot Graphic Resource Table and holds the boot logo you see when booting in UEFI.

This logo cannot be directly modified as it is builtin in the EFI firmware, unless you flash a new one.

However the ACPI table describing the logo could still be changed (not permanently) in an EFI application. GRUB2, and its modules, are EFI applications and so can change the content of the BGRT table for a one-time-boot.

This is what this GRUB2 module do.

Installation

Local installation:

$ make && sudo make install

grubver variable designates the matching grub version and is 2.04 by default. platform indicates the cpu platform architecture: x86_64 (default) or i386. DESTDIR variable is respected at installation.

A PKGBUILD is also provided for Arch-based distributions.

Usage

insmod hackbgrt
hackbgrt (hd0,gpt1) image=/relative/path/to/bmp|keep|remove[,x=123|center|keep,y=456|center|keep][,weight=1] [image=...]*

Where:

• (hd0,gpt1) is your ESP (EFI System Partition) as seen by GRUB2.
• image variable could take a 24-bit BMP splash path file, or the value keep, or the value remove.
• x and y variables could be used to position the image. You can use an absolute position, or center value or keep value.
• weight variable is use to add a weight (probability) to your image. Only useful if you use multiple image variables.

The Splash file should be relative to the ESP partition and should start with a slash.