I have just updated my wife's Iphone SE to IOS 12.1.4, and apparently this update makes the phone completely useless because it cannot get a signal.
When i rebooted it has full signal until the passcode is entered and IOS kicks in, then the signal dissapears or goes to 1 pin on the scale.
iPhone SE
Hello LAJ81,
Thank you for using Apple Support Communities.
I understand that after upgrading iOS on your wife's iPhone, there is an issue with connecting to your cellular network. I would recommend starting with the following support article for troubleshooting. The most applicable sections would likely be checking for Carrier Settings updates and resetting the Network Settings, but I wouldn't overlook the other checks also.
If you see No Service or Searching on your iPhone or iPad - Apple Support
Best regards.
IOS 12.1.4 Ihone SE
