They only need to store the changed part, and the firmware thing was always a thing, also back when it was possible to roll back updates. This reads like Micro

They only need to store the changed part, and the firmware thing was always a thing, also back when it was possible to roll back updates. This reads like Microsoft’s ‘the old new thing’ where they make up excuses for choices made by Microsoft and here for Apple. I presume the real reason is that Apple would say instead of preparing for the update to fail, it’s better to make sure it doesn’t fail in the first place.