I gave a talk at Open Source Firmware Conference this year, Reproducible Builds All The Way Down:
https://www.osfc.io/2023/talks/reproducible-builds-all-the-way-down/
Slides available:
It was well received, highlighting many historic #ReproducibleBuilds issues in firmware projects that I maintain in #Debian and touching on the hows and whys of Reproducible Builds.
Open Source Firmware can be a great example of 100% reproducibility, with a narrow scope of code, and is often a key part in early system boot!