In case you have accidentally updated to iOS 8.2, you can always downgrade your device to iOS 8.1.3, as Apple has not yet blocked the signing window for this.
Check out the guide below (Courtesy of GottaBeMobile) if you want to downgrade your iPhone, iPad and iPod touch to iOS 8.1.3 from iOS 8.2, which is compatible with the following iOS devices:
iPhone 6, iPhone 6 Plus, iPhone 5s, iPhone 5c, iPhone 5, iPhone 4S
iPad 4, iPad 3, iPad 2, iPad Air 2, iPad Air
iPad mini 3, iPad mini 2, iPad mini with retina display
iPod touch 5th generation
How to downgrade from iOS 8.2 to iOS 8.1.3
As iOS 8.2 is the latest version, you cannot update to an older version through iTunes or update. You will have to go through the following process.
Step-1: Head over to this page and download iOS 8.1.3 IPSW for your iOS device. Ensure that you download the correct IPSW firmware according to the model number of your device. Installing the incorrect firmware could damage the iOS device. The download size of these files ranges from 1.5GB to 2GB. Therefore, downloading the firmware will take some time
Step-2: Once you have the correct iOS firmware version downloaded, plug your iOS device to the computer using USB cable
Step-3: Launch iTunes
Step-4: Navigate to the device’s summary page and hold theOption/Alt on the keyboard. Or,Shift if you are using Windows
Step-5: While holding the key combination mentioned above, click Restore in iTunes
Step-6: Browse to the location where you have saved the IPSW file and open it. Now iTunes will begin restoring your iPhone/iPad and install iOS 8.1.3
Your device should now be running iOS 8.1.3. If you want to restore your backup, go to the device’s summary page in iTunes and click on Restoring Backup. Wait for some time until the process is completed, and your device should be back on iOS 8.2.