So you’ve upgraded your device to iOS 5 Beta, and would rather go back to a more solid user experience. Well, according to Apple, it is not possible to downgrade from iOS 5 Beta. It would be best to listen to their warning, but if you are daring and ready to dump iOS 5, then here are the steps to make it happen. As always, be sure you have a backup of your device in case you have any issues.
DISCLAIMER: WE ARE NOT RESPONSIBLE FOR ANY DAMAGE TO YOUR DEVICE BASED ON THIS TUTORIAL. USE AT YOUR OWN RISK
First of all, you will need a 4.3.3 ISPW and iTunes 10.5 Beta installed. These are prerequisites for this tutorial to work properly.
1. First, Put your phone into DFU mode. Make sure the phone is off and plugged into your computer. You can do this by holding down the power and home button for 10 seconds, then releasing the power button and continuing the hold down the home button. iTunes will tell you it found a device in recovery mode. If so, you’re ready to go. If you don’t see that message, try again.
2. Next, remove any host file modifications you made in the past for any Apple activation fixes. If you haven’t made any changes, you can skip this step.
3. Within iTunes, select the restore option, and select your 4.3.3 ISPW that you downloaded. Do not restore from backup, as there will most likely be issues.
That’s it, wait for iTunes to finish it’s thing, your device will reboot and you’re back in 4.3.3. And this will work on devices that used the activation bug for iOS 5 Beta.
There is however one more option to do this. It’s not as clean, and not as well proven, but may work. If the above fails, you can attempt the downgrade using TinyUmbrella.
First, Open TinyUmbrella and go to Advanced. Next, Uncheck the box next to “Set Hosts to Cydia on Exit”. This uses Apple’s Servers and removes the Cydia entries from your host file. You can now do a restore through iTunes 10.5 Beta back to 4.3.3.
You have now downgraded our device back to 4.3.3. Enjoy!