Painfully slow, that is. My husband has a 3Gs iPhone and he did the update on his phone before I did. Despite the download being over 350MB and a full backup is done of the phone before the new OS is installed, my husband’s update was complete in just under 2 hours.
Figuring it wouldn’t be any different for the 3G iPhones, I started the download in iTunes and went on to other tasks. Once the OS was ready for install, I grabbed my daughter’s phone and plugged it in. I pressed the magic “update” button and expected she would have the app folders, multitasking and other new features in a few hours. Five hours goes by and iTunes is still showing a backup is in progress, but there is only 1 progress bar. At this point, I’m very tired (I started the upgrade just after dinner) so I head to Google for some assistance from the virtual community.
The majority of threads I found related to long updates said doing a “restore” rather than an “update” on the 3G model seemed to work better. As I had just done a complete backup on her iPhone the day before, I figured I had nothing to lose by canceling the in-progress update and attempting the restore. So, that’s exactly what I did.
After canceling the update I unplugged her phone and restarted my machine just for good measure. After plugging her phone back in and launching iTunes I then selected the “restore” option. I selected her backup from the drop down list and crossed my fingers. Within 2 hours her phone had been restored to factory settings, iOS4 was installed and her backup file was loaded back to the device with everything intact.
The next day I proceeded to use the same method to update my 3G. I did a fresh sync before starting and as an added precaution I copied the photos from my iPhone to a folder on my computer in case anything went wrong. The restore method worked flawlessly and I was running the new OS within a few hours.
We have a friend who used the “update” method on their iPhone 3G and had to let it run overnight. He said the total time for the update was just over 10 hours!
If you choose to go with restore rather than update, do so at your own risk as it has not been listed as an official method for getting iOS4 on your device.
Oh… and after getting the new OS installed don’t expect to use multitasking and voice control on your 3G. Those features aren’t available on this model. Folders for apps and threaded email are a big improvement, though.