I just can't get my iPhone 5 (A1429 - UK GSM) to update, it's stuck on 6.1.1. If I try updating OTA, I get that "my software is up to date", it's the same if I try updating it through iTunes (11.0.4). I've downloaded the ipsw file for 6.1.3 from the Dev Center but when I try to force update with it via iTunes I get an error saying my iPhone isn't eligible for the requested build. I've definitely downloaded the correct ipsw; iPhone 5 Model A1429. None of the fixes I can find for this error seem to apply (and most seem to only be relevant when the phone has been jailbroken, which mine never has). Any suggestions, please?