This is an alright tutorial, and Rust is still pretty stable, but the QEMU implementation of RISC-V supervisor mode has changed a little bit and you'll need to fiddle with PMP and the MMU a little more.

I also found that there's a fair amount of code Stephen never introduces or talks about on the videos, and just has dropped in the repo. This can make cobbling together your own version of this a little tougher, but maybe a fun experience.