Right. They could add the riscv64 backend to the current compiler, and then cross-compile it from x86_64, meaning that the bootstrap chain for riscv64 would start at 1.37.0. No mrustc even needed.

That said, I feel like we may be talking past each other... what I'm saying is, to get support for riscv64, you don't need to do a full new bootstrap. Maybe I'm misunderstanding the point of the thread.