This problem only impacts people who have data working fine when they set the phone up as a new device, but lose data connectivity after a restore from a previous device backup. This is caused by APN settings from a previous jailbreak and comcenter patch or other modification to APN settings which can't be removed - essentially there is a phantom APN installed with the wrong settings for your LTE data plan (but worked fine on 3G). Other symptoms of this issue include: The SETUP PERSONAL HOTSPOT option missing in Settings --> General --> Cellular If you try to install a new APN, you're told that one already exists even though it doesn't Trying to access data gives you the error "Could not activate cellular data network - You are not subscribed to a cellular data service" Before beginning - you will want to have a backup of your iPhone backup in case you make a mistake! Yes, a backup of the backup. 1) Download and install iBackupBot for Mac or Windows (free version works fine, but this app crashes LOTS on OS 10.8 - just relaunch it and keep trying) 2) Open your backup and find the entry "mobile/com.apple.managedCarrier.plist" 3) Double click on the file to edit it (you can cancel the prompt for registration) 4) There is likely a more delicate change, but I preferred to wipe this file clean and let the iPhone 5 restore the correct settings. Replace the contents of this file with the following: Code: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <array/> </plist> 5) Save your change and close the application 6) On your iPhone, go to SETTINGS --> GENERAL --> RESET --> ERASE ALL CONTENT AND SETTINGS 7) Once complete, restore your iPhone from the backup you just edited Voila - enjoy LTE.