Apple has just launched iOS 8.0.1 and many users are having huge issues with their iPhone. All though the update is just small (73MB) it has created some issues with cellular reception with a lot of users (specially AT&T users) getting a “No Service” message. For those who haven’t updated to iOS 8.0.1 yet, we highly recommend you wait it out until more information about this issue is available, as of now we have several methods that should fix the issue:
UPDATE: Apple has pulled the update, users can no longer upgrade to iOS 8.0.1.
UPDATE 2: AT&T rep is advising users to upgrade via iTunes. Best option is to simply not upgrade.
Method 1 – Hard Reset: This should fix the No Service issue for most users. A hard reset can be done by holding the home button and power button at the same time until the white Apple logo appears on your screen. (mainly proven successful with iPhone 5S, iPhone 6 and iPhone 6 Plus users)
Method 2 – Removing the SIM card: While the device is off, remove the SIM card of your iPhone and put it back in, once it has turned on proceed to enter the correct PIN code. For several users this has fixed the issues
The method seems to be mainly working for the newer iPhones, if it hasn’t worked for you there is only 1 option left: Downgrading to iOS 8.