UPDATE 10/12/2011: My experience upgrading my iPhone 4 to iOS 5 was very different, it went flawlessly. It’s a phenomenal upgrade. My iPhone 4 runs faster and I have more functionality, what’s not to like? Want to know how to work around a slow iOS 5 update? Read Anticipating a slow iPhone/iPad iOS5 update?
If your iPhone OS 4 update hangs, read on: My iPhone update to iOS 4 downloaded quick enough then the process seemed to hang on “backing up”. The progress bar was farther along on my first attempt but after a couple of hours I felt something was wrong so I canceled and started over again. Two hours in I’ve barely made any progress.
The Restore process described here worked well for me. Your milage may vary. My apps, music in playlists, movies, photos in albums, contacts, calendars, email accounts and contents were all restored. Restore brought back all the app data I care about like Shazam tags, Flight Track info, Geocaching saves — and I remained signed in on FaceBook, Urban Spoon, Qrank and many others besides (Pandora excepted, I had to sign in again and I had to key in my PIN number again for AT&T voicemail).
FOLLOW UP: Here’s a story which blames Spotlight for the sluggishness Turn Off Spotlight Search For Performance Boost on iPhone 3G Under iOS 4.
WARNING: 3G owners beware, iOS 4 slows things down and I would not recommend it to you — especially since most of the new features won’t work on this model (but folders, threaded emails and a unified inbox does work). 3Gs users seem to happier with performance and benefit from most of the new features. I strongly suspect that my battery life is now also worse.
Please comment on your own experience using this method, or any other, so that other readers can decide on the basis of case studies what solution they’d like to try. It goes without saying that you should take backups before you apply this or any other update solution, Apple’s included!
After wasting six hours, here’s what worked for me …
- Be connected to the internet (so it can download the iOS 4 update).
- Connect your iPhone to your Mac via USB.
- Sync your iPhone (so you can restore to it later).
- iTunes>Preferences>General enable “Check for new software updates automatically” (to download the update as part of a restore).
- Hit the Restore button — and heed the warning “all of your media and other data will be erased” but “the newest version of the iPhone software will be installed”, fortunately you will restore your data from the Sync you just took (worked well for me). Then hit the Restore and Update button to continue
- Wait about 20 minutes while it steps through “Restoring iPhone software”, “Verifying iPhone software” and “Restoring iPhone firmware” until it pops us with “Your iPhone has been restored …” and then restarts your iPhone.
- When your iPhone restarts and appears in iTunes>Devices click on “Restore from the backup of ~’s iPhone (the Sync you took earlier) and Continue. Wait out however long it takes to restore your apps, music, movies, photos, contacts, calendar etc. (my iPhone had over 14Gb on it and it took over an hour to restore it all). Thereafter the iPhone will again restart and show up in your iTunes>Devices. Note that your software version is now 4.0!
iTunes>Devices>~’s iPhone …
Suggested reading: This video purports to show improvements in performance on a 3G between iOS 4 and 4.1 (note, not iOS 4.0.1) iPhone 3G (iOS 4.0) vs. iPhone 3G (iOS 4.1): Fight! [Video]
While waiting patiently on my initial update to work I searched the net to find that others are having similar problems: TekGoblin’s iOS 4 Backup Issues today | Apple Discussion Group Topic : OS 4 Update Stuck In ‘Back Up’ Mode
Answers: Slow loading iPhone upgrade; upgrade slows iPhone down; iOS 4 not recommended for 3G,
This appears to be a red herring, I tried this suggestion to no advantage:
What’s going on here? I think because the iPhone sends crash reports back to Apple when your iPhone backs up — yes I naively said that was okay once — that their servers are inundated with these reports in the rush as everybody upgrades simultaneously. After the backup begins try disconnecting yourself from the internet (Turn AirPort off in my case) to temporarily disable that. When the back-up is done the verification will fail. Reconnect to the internet (AirPort: On in my case) and hit the Update button to continue to completion. Here’s a topic that seems to confirm this: Topic: FIX: Extremely slow backup process (tested with 3GS)