If you had accidentally upgraded your iPhone, iPad or iPod touch to iOS 8.1.2 and want to downgrade back to iOS 8.1.1, then the good news is that you can downgrade as Apple seems to be still signing the iOS 8.1.1 firmware file. However, you will need to hurry up as Apple could stop signing any moment.
You will be able to downgrade back only to iOS 8.1.1.
You will be able to downgrade as long as Apple continues to sign iOS 8.1.1 firmware file.
It is important to take a backup of your iOS device to iCloud or using iTunes so you can restore from the backup if something goes wrong.
Apple doesn’t recommend downgrading so please proceed at your own risk.
Check real-time signing status
To find out if Apple is still signing the firmware file, check this website. Green rows with a tick means that Apple is still signing the firmware file, and you can downgrade from iOS 8.1.2 to iOS 8.1.1.
How to downgrade from iOS 8.1.2 to iOS 8.1.1
If Apple is still signing iOS 8.1.1, please follow these simple instructions to downgrade to iOS 8.1.1:download the ipsw from www.ipsw.me
Connect the device running iOS 8.1.2 to your computer.
Launch iTunes and select the iOS device from the top right corner, to the left of the iTunes Store button.
Hold the Alt/Option key on the Mac or Shift Key in Windows on your keyboard and click on the Check for Update option, instead of restoring. We were able to successfully downgrade from iOS 8.1.2 to iOS 8.1.1 using this step, but if you want to go by the book then you should use the Restore method, but it will be more time consuming. Important note: If you use the Restore method, then it will wipe the data from your device so please don’t forget to take a backup.
Select the ipsw file you had downloaded earlier.
iTunes will inform that it will update your iOS device to iOS 8.1.1 and will verify the update with Apple.
iTunes should now downgrade your iOS device to iOS 8.1.1.
After downgrading, the iOS device will restart. You should then see “Slide to upgrade”. Enter the passcode, and then wait for the downgrade process to complete. You may be prompted to activate your device.
That’s it. You should now be successfully downgraded to iOS 8.1.1.
Please note that Apple can stop signing iOS 8.1.1 firmware files any moment so downgrade back to iOS 8.1.1 as soon as possible. You won’t be able to downgrade back to 8.1.1 once Apple stops signing the firmware file.
Please don’t forget to let us know how it goes in the comments and drop us a line if you hit any issues.How to downgrade from iOS 8.1.1 to iOS 8.1
Edited by r3tribut10n, 10 December 2014 - 07:23 AM.