So you downloaded 'AppSync Unified' on iOS 10.2 before you knew the consequence. Yes, I've been there. You're now stuck in a boot loop and your phone keeps vibrating, trying to gasp for some air, it won't come on and the last thing you want to do is restore, you'll have to update and you'll loose your jailbreak! Well I've got the easy fix for you, you'll be able to restore without updating your phone! Here's the fix: Go to find my iPhone on your web browser on your computer or other device Get to where you are looking at the map, you should see you're bricked device on the map Click on your device and there will be a few options, the one you want is the restore option on the right Click on that restore button and enter your Apple ID and any other info required, and you should immediately see your iPhone start restoring When it's done, it will be a non-jailbroken iPhone but you will still be on the same iOS! Now just install a backup if you have one or just reset up your phone like new and re-jailbreak! Hope this helps!