Plug it back into i Tunes, update it, and choose "restore backup".
Apple has already released i OS 10.3 for i Phone i Pad and i Pod touch this March.
It doesn't matter, you can enjoy all the features i OS 8 brings to i Phone 6 by updating your elder mode of i Phone/i Pad/i Pod touch to i OS 8.
Just download and install i OS 8 on your device with the detailed i Mobie Guide.
I updated with i Tunes on my PC but it says that it cannot update my i Pad! You mentioned though that you "bought" the i OS 8.1.1 IPSW. If you paid for it, you should immediately demand your money back.
I want to install i OS 8.1.1 but current version on the i Pad is 6.0.1. Chances are, if you were asked to pay for it, it is a corrupt image, a pre-jailbroken hack, a misstated blank file, or simply the wrong IPSW for your build of i Pad.
Check How to Update to i OS 8 Over the Air or Via i Tunes Once the i OS 8 is installed on your i Phone, i Pad, i Pod touch successfully, most of you think the whole process is finished.
Before performing i OS update on i Phone i Pad, it is strongly recommended to do some pre work before you do any update.
If you're running a the developer or public beta, Apple might push you an update if the build numbers are different (we're still checking on that).
Apple has just released i OS 8.0.2 for i Phone, i Pad and i Pod touch, which includes bug fixes and improvements, and also addresses the issues with cellular connectivity and Touch ID issues that affected i Phone 6 and i Phone 6 Plus users.
Artenstein is presenting his findings at the Black Hat security conference later this month.
The vulnerability, which Artenstein is calling Broadpwn, allows hackers to execute code (essentially letting them control the device remotely) without any interaction on behalf of the user.