A few months ago the topic was already in Leadership meeting + Mailinglist. It is about creating a spec that specifies the handoff between coreboot and payload via FDT. It is not just for coreboot though (u-boot, oreboot and EDK2 as well). Its been a while now, the spec grew and I don't want to keep the community in the dark. For more information here is the spec: https://docs.google.com/document/d/1WxEUlCsXpc17DkJhL3XVkOW7e_KIt_zcc9tQ1trO...
Feel free to review (do your worst so that we get something decent), contribute and enter the meeting that is going on every week: https://meet.google.com/gha-shza-wnw
greetings Max