HackBGRT
HackBGRT is intended as a boot logo changer for UEFI-based Windows systems.
Summary
When booting on a UEFI-based computer, Windows may show a vendor-defined logo which is stored on the UEFI firmware in a section called Boot Graphics Resource Table (BGRT). It's usually very difficult to change the image permamently, but a custom UEFI application may be used to overwrite it during the boot. HackBGRT does exactly that.
Usage
Important: If you mess up the installation, your system may become unbootable! Create a rescue disk before use. This software comes with no warranty. Use at your own risk.
- Make sure that your computer is booting with UEFI.
- Make sure that Secure Boot is disabled, or learn to sign EFI applications.
- Simple Windows installation:
- Get the latest release.
- Start
setup.exe
and selectI
(install). - The installer will launch Notepad for modifying the configuration.
- If you need only one custom image, the defaults are fine.
- Otherwise, check out the examples in the configuration file.
- The installer will launch Paint for creating the image(s).
- You can create multiple images by using Save As.
- Be sure to always use the 24-bit BMP/DIB format.
- If Windows later restores the original boot loader, simply reinstall.
- If you wish to change the image or other configuration, simply reinstall.
- Installation for Windows with another boot loader (e.g. GRUB):
- Extract the latest release to
[EFI System Partition]\EFI\HackBGRT\
. - Set
boot=\EFI\Microsoft\Boot\bootmgfw.efi
inconfig.txt
. - Point your boot loader to
\EFI\HackBGRT\bootx64.efi
.
- Extract the latest release to
- Installation for all operating systems:
- Extract the latest release to
[EFI System Partition]\EFI\HackBGRT\
. - Set
boot=
to your preferred boot loader inconfig.txt
. - Set
\EFI\HackBGRT\bootx64.efi
as your default boot loader withefibootmgr
or some other EFI boot manager tool.
- Extract the latest release to
Configuration
The configuration options are described in config.txt
, which should be stored in [EFI System Partition]\EFI\HackBGRT\config.txt
.
Images
The image path can be changed in the configuration file. The default path is [EFI System Partition]\EFI\HackBGRT\splash.bmp
.
The image must be a 24-bit BMP file with a 54-byte header. That's a TrueColor BMP3 in Imagemagick, or 24-bit BMP/DIB in Microsoft Paint.
Multiple images may be specified, in which case one is picked at random.
Building
- Compiler: GCC targeting w64-mingw32
- Compiler flags: see Makefile
- Libraries: gnu-efi