Could not restore iPhone after 7.1.2 update
As a number of other people have posted here, I've encountered some problems with the iOS 7.1.2 update on my iPhone. Unlike most of the others, I've tried a number of possible solutions before resorting to asking here, and I have details of my efforts to share. My experience with this problem over the past twenty-four hours suggests that the standard advice I'm seeing given is insufficient for those of us having this issue.
This started around 1 am EDT last night (this morning) when I did a standard sync of my 16 GB iPhone 4 in iTunes 11.2.2 in order to install a couple of newly updated apps. I will point out up front that it was not my intention to update to 7.1.2—I was still on iOS 7.1.1 and intended to remain there until I'd seen reports of others' experiences with the update. (I've been burned before by issues with an iOS update, and I tend to be cautious about them now, as it is a one-way trip.) In fact, my iTunes had not yet notified me of the 7.1.2 update; I knew of it from it having appeared as a notification on my phone itself.
At the end of the sync, however, iTunes told me that it could not install one of my updated apps because there was not enough space. I normally try to keep about 1 GB free, so this seemed odd, especially considering that I had not added anything sizeable since my last sync earlier in the day. I was surprised to see that iTunes reported only 300 MB free on my iPhone. The culprit appeared to be the opaque "Other" category, which had since the prior sync ballooned from less than 1.8 GB to nearly 2.5 GB for no apparent reason.
(Side note: Apple's insistence on not defining the contents of "Other" to users and not providing any reasonable means of cleaning it out continues to be an issue, which is compounded by its tendency to grow over time. Is it too much to ask that some housekeeping be enabled for this?)
I have in the past had fairly consistent luck with purging old, outdated data from "Other" by doing a full reset and restore on my iPhone, so I set out to do this. Unfortunately, iTunes downloaded and installed iOS 7.1.2 instead of the installed 7.1.1, and I had no opportunity to change that. I was annoyed by this—a system reset should not force an OS update—but I didn't expect any significant problem from it.
Once the reset completed, I got my first sign of real trouble: an error saying that my iPhone "could not be activated" and that I needed to call Apple. As it was roughly 2 am EDT by then, this was not an option at the time. After I accepted that error message, however, iTunes showed my phone with its correct name and information, and began the process of restoring the last backup (which had been made during that sync attempt an hour earlier). After several minutes, I got another error message saying that this backup could not be restored because it was "corrupt" or "incompatible".
I was, at this point, prepared to simply accept that I would have to redo everything, and so started setting things up in iTunes so that I could pack it up and go to bed. I soon discovered, to my dismay, that while iTunes gave no indication that anything was wrong with my phone at this point, the phone itself was stuck on the pre-activation screens, demanding to be connected to iTunes to complete activation. iTunes itself revealed no options I could readily locate for initiating activation manually, and if I proceeded through the setup screens on the iPhone for the option of restoring from a backup, I simply ended up back where I was before after several minutes, with the phone demanding it be connected and iTunes saying the backup couldn't be restored.
I gave up around 5 am EDT and went to bed. Later this morning I tried working with it some more. This time, I retrieved several of the last few days' mobile backups from my Time Machine backup (from ~/Library/Application Support/Mobile Sync/Backup, using Tri-Edre's Back-in-Time) and fed them into the phone, but each one returned the same "corrupt or incompatible" error. This included backups dating as far back as a week ago, prior to 7.1.2 becoming available.
At this point I tried running setup on the iPhone as a new device. Fortunately, all the key information is tied to my Apple ID, so it was suitably reactivated with my carrier, and it knew which apps, music tracks, videos, pictures, and books were to be synced to it, so I didn't have to manually re-add them all. But it of course does not have any previous settings or local data stored, and my 178 apps that had been meticulously arranged into folders were now spread across 12 pages in alphabetical order. I'm still slowly going through everything to reset those missing settings and folder structure.
Ultimately, I haven't lost anything of real importance besides time. Besides my iTunes backups, all my "real" data is kept in apps that sync with their OS X counterparts in some form (like Evernote and Dropbox). I had recently downloaded photos, so I have not lost any of those either, though since I don't save them to iCloud (for several reasons), those which I had retained on the phone in Albums are no longer there and will need to be re-collected and synced. Primarily, the only things that appear to be irretrievably lost are my call and SMS logs (iMessage history is still in OS X Messages, and voice mails are stored by my carrier), and saved data from games that don't link to Game Center. Not a big loss, to be sure—I'm still weighing whether it's worth paying the $50 to register iBackup Viewer Pro, which appears to be the only tool which claims to be able to extract data from encrypted iOS backups, in order to restore that data to the iPhone.
My purpose in posting this, then, is not to ask for solutions to get my phone useable again—I already have that—but rather two other things. First, I wanted to present as much detail as I could about this issue to the community, since the other threads I've found here asking about this problem have yet to get past the initial "reset and restore from backup" advice, and my experience indicates that this isn't necessarily going to help, but resetting and setting up as a new device, then resyncing with your Apple ID/iCloud/iTunes can at least make the device functional again. I'll also point out that unless you encrypt your backups (which I do, because, well, duh), there are several utilities available, some of which are completely free, that can extract your data from your backups. Some of them even claim to be able to return that data directly back to the device. Given that this "corrupt or incompatible" error appears to not be stating the situation accurately, it's likely that your data is still intact in your backup despite the error message—iTunes just can't restore it directly to the device. (If you do encrypt your backups, the only utility I've found that claims it can extract anything from them is the aforementioned $50 iBackup Viewer Pro.)
Second, I want to find out where this problem comes from: I had at first assumed that the "incompatible" message came from having a later version of iOS on the phone than had been present on the backups (though the official line has always been that while you could not restore a backup to an older iOS, there shouldn't be an issue with restoring to a newer one), but what I've seen on this forum indicates that this seems to be a problem in 7.1.2 itself being unable, in at least some cases, to accept backups from a previous iOS. Is this a viable hypothesis, or is there another factor at work here? If it is something specific to 7.1.2, is fixing it a priority?