Comment by circularfoyers 10 months ago
I still don't understand why Apple haven't changed their update model to A/B partitions, so if an update can't boot, it boots the previous partition. Android has been doing this for a while and Fedora Silverblue/IoT does the same thing, both of which I've found really useful in the past. If communicated well, it would elviate the update anxiety many people I know have with their iPhones.
I believe the point isn't to let you rollback at will, but it'll automatically rollback if it fails a boot check, so before anything is written to the filesystem. However, it's worth noting that Fedora Silverblue/IoT let's you rollback at will without problem.
> and Fedora Silverblue/IoT does the same thing,
Silverblue uses ostree, which AIUI uses hard links in a single filesystem. This is probably better most of the time, because it means minimal storage overhead, though it means you can't change filesystems over an update and you don't resist filesystem corruption.
It will not be able to reliably work with the A partition once B boots the first time - the update process even for many minor releases will trigger local and cloud data upgrades, and there are security reasons to not leave the option to leave older/unpatched versions runnable.
I don't think I've had a software update fail since iOS 7 beta 1 - and that was an issue with updating local data on first boot, so any attempt to revert to the prior OS without a wipe would have been pointless.