I got this AT&T iPhone 5 purchased overseas for $800 plus tax.

As soon as I got it, I tried to restore it to bypass the activation screen required by AT&T. But restoring didn't go smooth as planned. Now the phone is stuck in recovery mode. And every time I place it in DFU mode, then restore with iTunes I get an error 21, if not in dfu mode 1603,1604, 1611 errors come out.

When restoring using DFU mode, what I notice is that iTunes has the loading label ‘preparing to restore iPhone’. The device on the other hand turns off, and comes up with the Apple logo and the daisy/spinning wheel. The wheel spins for about a quarter only and get stuck, and soon after reboots and goes back to Apple logo. After that is the popular iTunes and USB logo. Then, iTunes gives an "iPhone cannot be restored. An unknown error occurred (21)" something error. The process repeats every time I try to restore in DFU mode.

I've tried almost everything online relating to this issue: device off and hold home button while connecting the lightning connector and wait for the iTunes logo and USB to show up before releasing home button, for example. Done it for countless times, in 4 different computers.

I've tried it on 2 PCs with Windows 7 64-bit, a MacBook Pro and a Windows XP. The IPSW file I'm using is the 6.0.1 for GSM which is appropriate for my GSM device.

Been stuck for almost a week now, will be really sad if this is a hardware failure, it would mean additional expense for warranty.

Any other suggestions I should try for a fix? I really want to start using this device.

4 Answers 4


I'm not really sure if we are in the same boat. I had been stuck in DFU mode after restoring my iPad to iOS 6.1 without activating it. I have tried using iTunes in restoring the firmware but it was stuck on the iTunes and usb logo just like you. What I did was to use redsn0w to restore my iPad. You can use it without jailbreaking your phone. Hope this helps.


I found you a link for all of your errors. All the errors you listed have been gathered to a single Apple Support page. Click the error number to jump to the relevant section or specific page.


I've got "IPad could not be restored Unknown error (21)" after upgrade to new version failed. The following steps from https://discussions.apple.com/message/18064040#18064040 allowed me to reset an IPad, and then I've restored it from ICloud backup.

Power off the iPad completely (wait for the progress spinner to disappear). Hold the Sleep/Wake switch AND the Home button down for a full 10 seconds. After 10 seconds (the second time you'll see the Apple logo on the screen) release the Sleep/Wake switch while still holding the Home button.


Solved by pushing it out of Recovery mode cycle by using ReiBoot (https://www.tenorshare.com/products/reiboot.html). I am sure there are some other apps that can do this too. It's very simple to do, I just installed it, run it, plug the iPhone in computer via USB. It detects the iPhone, offers a "push out of recovery mode" button of sort. Click the button and voila!

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .