With Rust, you can do what I did with my OS. It can compile out of the box. The kendryte has a "BSP" (base support package) that is essentially a minimal OS, but it is written in C.
Yeah, I was thinking more about what to do with the OS afterwards. That board has lots of things on it, including wifi, so I'll probably would like to use some of that.
It would be unfortunate to have to re-implement the wifi driver in Rust, but I suppose I'll just have to link parts of the C toolchain instead, creating Rust wrappers, etc.