Error 29 When Updating to iOS 4.0 or Restoring iPhone

Some users have reported an issue in which iTunes displays the error message “The iPhone “name of iPhone” could not be restored. An unknown error occurred (29)” when attempting to update to iOS 4.0, or perform a restore on an iOS 4.0 device.

This issue appears to affect primarily users who have replaced their batteries or some other hardware components through a service such as iFixit. Error 29 indicates a hardware issue, which means that iOS 4.0 may be (accurately or not) triggering some compatibility issues with after-market add-ons or replacements.


Some users have been able to resolve this issue via the use the utility iRecovery. Instructions are here.


  1. says

    My experience: some iTunes installs are missing iPhone drivers, leaves the iPhone in a Recovery Loop error 29. I Uninstalled iTunes (10.0), installed iTunes 10.1, reconnected the iPhone and it was able to communicate. I did have to use TinyUmbrella to kick it out of the Recovery Loop. (/|\) Peace

  2. says

    Updating to iOS 4.2 software on my iPhone 3GS failed, locked phone to the sync screen and hid the device from my pc. iTunes only option to restore device which did not work and reported error 29 as a final result.

    Remedy as shown on previous comment was to retrieve my old OEM battery and re-install it. Thank God I had not tossed it.

    Iphone immediately recognized updated and now working fine except I have an old worn out battery.

    Figure I will put in the new replacement battery and not sync to itunes unless I have the old battery installed.

  3. says

    Wow! Been trying all day on error 29, then on 3014 adn 3194 while trying to downgrade to early firmware. Slipped in original battery and voila!

  4. Robert says

    Anyone know what the deal is with replacement batteries? I have a 3Gs that had an APN: 616-433 battery in it. Life was down after about 400 cycles, so I replaced it with a new 435 battery. Nothing wrong with the battery, but restoring 4.2.1 fails with error code 29. Put the original battery in and it works fine. I’ve Googled and found a lot of references to update/restore error 29 due to battery replacements, but nothing official. For my situation, is a 433 battery mandatory?

  5. says

    Ill be darned. This piece of junk got stuck in recovery mode. I put the original battery back in (Thank god I didnt throw it out…like mark) and this damn thing worked again. How the hell does apple know the difference in the batteries. Hahahahah. I love apple and there crazy issues. Thanks a bunch!

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