Presently, arm64 isn’t a supported architecture for
coreboot in emulation, mainly due to the fact that the port we have runs in 32-bit for
bootblock and romstage stages. I would work to re-structure this and get these stages
running in 64-bit.
Just wanted to make sure you know that we were also planning to rework
the whole bootblock and romstage mess on ARM64 in the near future for
a Chromium project. When you get to that part in your project please
let me know what you're planning to do so we can avoid doing the same
thing twice and stepping on each other's toes.
(Also, not sure if you know this already but we did use to have an
emulation/foundation-armv8 port already that I think even somewhat
booted as some point. It just fell into disrepair with latter changes
but it might still be a useful starting point.)