@tlaurion @mkukri i keep coming to irc just as you're leaving! yes, basically the t480 patch in lbmk is in a tree where that is the only thinkpad at the moment, so it can just hack up coreboot whatever it wants. mate has told me he will tidy up the t480 patch as part of general upstreaming efforts. libreboot uses a different coreboot tree for all other thinkpads. libreboot is a multi-tree build system design, where coreboot is concerned:
https://libreboot.org/docs/maintain/
perhaps do the same in heads?