Comment by jcalvinowens

> the system would automatically fallback to the previous version by just switching the bootslot used.

That's the hard part though.

It's shockingly common in my experience to have an A/B boot setup, but no actual logic in the userspace application to switch back to the other partition if something goes wrong. It's just a defense against somebody pulling the plug during the OTA, it doesn't protect against software bugs at all.