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Level 1

8 points

4s Failed 9.2.1 upgrade and crash

My iPhone 4s crashed during a routine wifi upgrade from ios 9.2 to 9.2.1 this evening. Prior to the upgrade it was working 100% OK! It now refuses to reboot and just comes up with the iTunes & cable logo.

I have made at least 10 attempts to upgrade/restore in iTunes with a network connection, all of which failed at the same point with an "unknown error (29)"

message.

The failure occurs at about 55% on the progress bar, after successful iPhone software installation and verification at the start of the firmware verification process.

Any ideas as to what to try next would be greatly appreciated please?

Thanks!

iPhone 4S, iOS 9.2

Posted on Jan 24, 2016 3:54 PM

21 replies

Feb 11, 2016 6:56 AM in response to Wjohnu

Hi Wjohnu,

Luckily I found a friend of mine who had an old iPhone 4.

I put this battery in my 4S and it has worked!

Do you or TJBUSMC1973 know if I can replace this battery with my purchase from Amazon?

If I do, at some time, would the next software update (9.2.2? download OK?

I would like to thank you and other members of the Forum for sorting this mess out for me.

panther600

Wjohnu Author

Level 1

8 points

Feb 11, 2016 8:03 AM in response to panther600

HI Panther600

Well done, I'm glad it worked for you too! I think you will find that your Amazon battery will work fine now, but you will have the same issue at the next iOS update!

I have returned my "genuine OEM" £10 battery for a refund and the supplier informs me that his new stock will overcome the upgrade issue. Similarly I checked out a more expensive £20 battery and the supplier actually did the upgrade with a 4s and confirmed success without issue. So, I think the suppliers are now aware of the problem and new production batteries will overcome the issue, you just need a reliable source.

Feb 11, 2016 8:11 AM in response to Wjohnu

Hi Wjohnu,

Thanks very much for that information.

If you can find out where and when the new battery comes out, please get in touch.

Thanks, once again.

panther600

chetna1

Level 1

0 points

Feb 20, 2016 11:13 AM in response to Wjohnu

Hi, I just found this discussion forum, fortunately just in time, as I had lost all hope of reviving my phone.

All this exactly happened with my Iphone 4s after 9.2.1 update finished, it didn't switch on, upgrades/restoring through iTunes failed at about 60%, just when firmware was being restored, citing unknown error 29.

Had tried everything, but couldn't get it fixed.

After reading this I realized I too had the battery replaced about a month ago, and have the old one too. Finally, something explains all this.

I'll get the old one put back in it. Hope it will solve my problem too, its been a tough week with a dead phone!

Thank you for sharing this, it really helped.

Chetna

Feb 22, 2016 6:18 AM in response to chetna1

Hi Chetna1,

I,m very pleased that you found the answer to this problem!

Like you, I was as confused as you were until I came across the solution on this Forum.

Hope everything works for you,

Best Wishes, panther600

djorkaef

Level 1

4 points

Oct 21, 2016 5:14 PM in response to Germoline

Had a very similar issue: bought a broken 4S and replaced the screen and battery. It was not an orginal battery. Everything worked until I did the IOS update. It was to 9.3.5. To Phone did not start and wanted iTunes to link, iTunes factory repair crashed on error 29. After some hours I put back in the Original battery, did a factory repair with iTunes again, and it worked. Firmware is on latest version now. Put the old battery back in and still works. But I fear a next upgrade... should not forget this. Thanks for your help.

4s Failed 9.2.1 upgrade and crash