Yesterday along with the hardware announcements, Apple released iOS 9.3.
I updated my phone without any issues but the update to the old iPad2 did not work. It would loop on the setup screen and each time fail when it tried to authorise itself with Apple’s servers.
As you can see from the above link it was mainly iPad2’s with Cell and GPS functionality affected.
The usual way to recover from this type of situation is to boot into recovery mode and restore. You did backup before you started your upgraded? I had and so soon got everything back, but do remember to directly attach via the iPad cable direct to a USB port on the computer, for some reason I could not get it to work using a Thunderbolt Hub.
BOOTING INTO RECOVERY
- With the device is OFF, press and hold the Home + Power buttons together until the screen turns ON.
- Now, connect your phone to the PC using USB cable and while keeping the Home button pressed.
- When you see a screen iTunes icon and of a USB cable, release the Home button.
I left my iPad connected to the computer during the above as its much easier then trying to plug it in while holding home button. People say that does not always work but it did for me.