promethee

"Promethee loads script.js from the boot volume and runs it. That script is your bootloader. If you can do it with UEFI services, you can do it in JavaScript."

"Your entrypoint is script.js. The run target copies it to the UEFI FAT volume as \script.js."

"var gop = efi.SystemTable.BootServices.LocateProtocol(efi.guid.GraphicsOutput); if (gop) { var red = { r: 255, g: 0, b: 0 }; gop.Blt(red, 'EfiBltVideoFill', 0, 0, 50, 50, 200, 120, 0); }"

"Duktape tooling requires Node.js (used to generate sources). The build is freestanding; only minimal libc stubs are provided. If this makes you grin, you are probably holding the torch."

Promethee exposes UEFI bindings to JavaScript so script.js can be loaded from the boot volume and executed as the system bootloader. The run target copies script.js to the UEFI FAT volume as \script.js, making that file the required entrypoint. JavaScript code can invoke UEFI services such as locating the GraphicsOutput protocol and issuing Blt operations to draw pixels. Tooling relies on Duktape with Node.js to generate sources. The build is freestanding with only minimal libc stubs provided, targeting low-level use and experimentation by developers comfortable with boot-time environments.

Read at Codeberg.org