Yes, there should be firmware updates for the kernel in flash. (And we haven't really figured out how to handle that yet.) But such firmware updates likely hav

Yes, there should be firmware updates for the kernel in flash. (And we haven't really figured out how to handle that yet.) But such firmware updates likely have different constraints and a different schedule than your kernel-in-production updates. People will likely have much different requirements for the kernel in flash than for the kernel in production. It may be that for your use case and threat model, they'd be the same - but that's up to you to figure out and decide.