This article is a nice addition to the community since rarely is a complete rewrite of a firmware corpus possible. Speaking of Rust and host or boot firmware, the recently published https://techcommunity.microsoft.com/t5/surface-it-pro-blog/s... provides a nice experience report. Other work on moving Rust into EDKII for UEFI style firmware https://github.com/tianocore/edk2-staging/tree/edkii-rust is described in https://uefi.org/sites/default/files/resources/Enabling%20RU... and https://cfp.osfc.io/media/osfc2020/submissions/SLFJTN/resour.... There's also guidance on Rust for firmware in a book chapter https://link.springer.com/chapter/10.1007/978-1-4842-6106-4_....