Here is detailed guide how to downgrade iOS 8.2 iPhone back to more stable iOS 8.1. Besides that the latest Apple’s mobile software iOS 8.2 has brought forth quite a few new features unfortunately it includes some bugs. In case you faced with some of that issues be it related to battery, Safari or else, as Apple is still signing iOS 8.1, you can downgrade.
Important to remember that this downgrade will not allow you to achieve a jailbreak of any kind. As iOS 8.2, iOS 8.1.3 is not yet jailbreakable, and thus, by reverting to iOS 8.1.3, you will avoid the performance issues that are caused by iOS 8.2 update.
So if you device is still on iOS 8.1.2 and below, it is recommended not to update to iOS 8.2 or iOS 8.1.3.
This guide is useful for only those users whose devices have been updated to iOS 8.2 and need to be downgraded back to more stable iOS 8.1.3. Unfortunately you cannot downgrade iPhone iOS 8.2 to 8.1 version as Apple had stopped signing the firmware.
The iOS 8.2 battery related issues have been well documented, but there are other problems besides that. Safari issue another one, and if you use browser every day, dropping back to iOS 8.1 really help.
As Apple is still signing iOS 8.1 the downgrade is still workable:
Step 1: First thing you need to do is to back up your iOS device to keep in safe your personal data. You can do this through iCloud, or indeed through iTunes.
Step 2: Now download iOS 8.1.3 IPSW specific to your device.
Step 3: Launch iTunes, hold down the Option key (Mac) or the Shift key (Windows) in iTunes, and please choose the Restore iPhone option. Find the IPSW that you downloaded in Step 2, and then select it.
Step 4: Once iTunes has done its job, you should be able to enjoy iOS 8.1 without bugs.
Again, downgrade iOS 8.2 iPhone to the more stable iOS 8.1 is not indefinite, and so if you are having some problems with iOS 8.2, please follow the above guide to avoid being stuck without the choice.