I would love to see details of iBoot. How they built a memory safe bootloader with just "a modified C toolchain" is a pretty important detail. Did add they another language to the toolchain or add a special --memory-safe flag to a forked C compiler?

Annotations on top of C, compiled through their private fork of LLVM. Here's what it looks like on our side: https://saaramar.github.io/iBoot_firebloom/

Fascinating stuff!