Having the same exact problem with my son's iPhone 7. He upgraded to 14.01. Got the cellular error. I tried to upgrade to 14.1 - upgrade failed. I tried to restore from backup - phone went into cycle between Apple logo and black. I forced phone into recovery mode and restored to factory settings. This worked but still have the cellular error, therefore can't even activate the phone now.
I found this URL - https://support.apple.com/iphone-7-no-service/other-countries
Going to call Apple today and see what they say.
JK007
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
From
Toronto, ON, Canada
Post
Replies
Boosts
Views
Activity
At the poster below, Bug_reporter - dude I couldn't even get into the that menu when I got the error.