Way out of my depth! However, the stuff I saw the folks from Oxide [1] talk about comes to mind. Hardware stuff with Rust. If you want to look at a specific project, Hubris [2] is a kernel for "deeply-embedded" systems.
Hubris is a part of booting on our systems in that it executes on both our root of trust and on our service processor -- but both of these execute long before the host CPU. To understand how we boot our host CPU (AMD Milan) on an Oxide compute sled, see my OSFC 2022 talk[0][1], as well as the episode of our Oxide and Friends podcast on holistic boot.[2]
[1] https://oxide.computer/blog/building-big-systems-with-remote...
[2] https://github.com/oxidecomputer/hubris