I just did an Untethered TaiG Jailbreak on an iPhone 5 running IOS 8.1.2 Just having trouble trying to install applications onto the phone. I tried installing the downloaded IPA through a few different applications but they all fail. UPDATE: Turned out it was a SYNC froblem. I had to update APPSYNC for IOS8. I used the instructions on this site to update APPSYNC for the installed IOS version through Cydia. Now installation of IPA works fine.