I want to first thank @mateidibu for his work at mateidibu/coreboot-flake: Build coreboot via a nix flake - Codeberg.org. To say that it’s been the perfect reference point on implementing this using Nix would be an understatement.
Snowboot aims to be more or less like lbmk, but with greatly reduced build times.
The project is currently being hosted in Codeberg and I’m currently dealing with all the automation necessary to make adding boards as simple as copypasting files onto a folder (more or less).
Here’s a screenshot of a working BIOS (using SeaBIOS as a payload) for QEMU:
Improvements are welcome, there is still a lot of work to do.

