-
…in reply to @CaseyNewton
CaseyNewton Could be anything, but you could generally assume: - Decompressing upgrade files - Backing up your data (possibly remotely, probably compressed) - Migrating system data to new format(s) - Upgrading settings/config to new "stuff" You could ask Apple to tell you (LMAO as if).
-
…in reply to @rockerest
CaseyNewton Basically a "good" "prepare" phase should be making it failsafe... which means copies, backups, and a rollback procedure if something goes wrong. Presumably your phone is protected (encrypted) by something, and that needs to work whether the upgrade works or they have to go back.