So... you can use e.g. systemd-boot, and BSDs are easier too. Linux distros are generally easier. It works like normal firmware (but it's Libreboot). EDK2 integration is only part of a general effort to modernise Libreboot. You can find the upstream here: https://docs.mrchromebox.tech/ - Libreboot has integrated the EDK2 part of this project. Matt (mrchromebox) has been helping me. He maintains this payload for Chromebooks but it works on other boards. A lot of people don't know but pretty much every major computer vendor you buy from will ship with a variant of EDK2, though they ship proprietary forks. MrChromebox is an open source version, made specifically to boot as a coreboot payload. Matt maintains it for Chromebooks so that you can run normal Linux distros on those devices, and it offers a lot of really nice features. It's a huge project. Matt has been doing it for years. I'm planning to add his Chromebooks to Libreboot as well, at a later time, working with MrChromebox when I can.