BGRTInjector

Changes the boot screen image on a UEFI computer.

This is a remake of Ben Wang's windows_custom_loader.efi, the source code of which is long lost. Several incompatiblities with non-Apple UEFI implementations are addressed, and you can now replace the logo without recompiling the whole program.

Requirements

UEFI firmware (some old EFI firmwares might be supported as well)

Installation

Run BGRTInjector.efi either manually or automatically before your OS loads. You need to disable Secure Boot or sign it on your own, obviously.

Installation on rEFInd

Put a release build of BGRTInjector.efi (driver mode) into ESP:\EFI\refind\drivers_x64 and reboot.

Installation without 3rd-party bootloader

Put a release build of BGRTInjector.efi (Windows loader mode) into your ESP volume and set it as the default loader. This can be achieved by putting it to ESP:\EFI\boot\bootx64.efi. (Firmware on some devices will load Windows first which is a violation of the UEFI standard. You might need to manually register a UEFI boot entry on these systems.)

Usage

Customize the image

To customize the image, put a 24-bit BMP image named boot_image.bmp into the root directory of your ESP volume (where BGRTInjector.efi lives).

Change the built-in default image

Convert a 24-bit BMP image to C-style array initializer, replace default_boot_image.bmp.inc and compile. To do the convertion you can use bin2array:

python3 bin2array.py -O default_boot_image.bmp.inc your_image.bmp

Building

Flags:

_DEBUG: debug output and more pauses to see the log on the screen
LOAD_WINDOWS: Windows loader mode. It will automatically search for EFI\Microsoft\Boot\bootmgfw.efi and start it after BGRT table has been injected

Windows

Requirements:

Visual Studio 2017 or higher
C++ desktop development tools
MSVC C++ build tools (for architectures you need)
MSVC C++ Spectre-mitigated libs (for architectures you need)
QEMU

Open BGRTInjector.sln in Visual Studio and click Build Solution.

zwj4031/BGRTInjector