iOS 8 debuted and it has already undobtedly found its way to plenty of devices. A big chunk of the likely belong to people who register for Apple’s developers program but aren’t actually developers. For the time being, iOS 8 is buggy and apps will crash constantly, but don’t grieve there is a way to go back to iOS 7.1.2 (or whatever the latest build might be at the time you choose to roll back).
These are instructions on how to downgrade from the iOS 8 Beta to iOS 7. You will only be able to downgrade to the latest iOS 7 release, which is iOS 7.1.2.
Before attempting any downgrade, please be sure to backup all of your information.
1. Download the latest iOS 7 firmware for your device from here. Note, that you can only restore to the latest firmware Apple is signing ( 7.1.2. in this case).
2. Launch iTunes
3. Place device into DFU Mode. Here is a full tutorial on how to put your iPhone into DFU mode.
Press and hold the Home button and the Sleep/Wake button at the same time. After 10 seconds release the Sleep/Wake button. But continue holding the Home button until iTunes pops up a message telling you that it has detected an iPhone in recovery mode.
The iPhone screen should remain black
4. Hold down the Alt/Option key (Shift on Windows) and click the Restore iPhone… button.
5. Select the firmware file you downloaded earlier from the window that appears and click the Open button.
When asked to confirm the restore click the Restore button.
6. iTunes will run the process of the restore/downgrade and after about 10-15 minutes, your device will be freshly restored to iOS 7.