Restoring from IPSW. Unable to connect to gs.apple.com (error 3014)
Enter DFU Mode, and then try a restore. Method:

First, plug the iPad into your computer, and then power it off. Make sure iTunes is running on your PC.

Now press and hold both the Power button and Home button simultaneously, until you see the Apple logo. Now let go of the Power button while still holding down the Home button. iTunes can now associate with the device and is told that the iPad is in Recovery Mode.

Finally, simply Restore your iPad to the ipsw file that you downloaded (or just restore, whatever your choice is).

Just in case you didn't know, in order to restore an iOS device to a certain backup/ipsw file located on your Windows computer, shift-click the Restore iPad ( / iPhone / iPod) button in iTunes and find &amp; pick the file manually.

(Note: There is a tool I know of called Cydia Impactor. There's actually a desktop version of it as well. Unfortunately, however, it apparently only works with iOS 8.3 and 8.4 in the jailbreak version of the tool.)