My iphone wont keep a signal and settings app crashs when i go to cellular

I started having the same issue with my phone. First it wouldn't show anything besides "Searching...", and now it cycles between 5 bars with LTE indicator, 5 bars with no LTE, and 1 bar with no LTE. Trying to go to the Cellular page in the Settings app crashes to springboard.

I've tried restarting the phone, reinstalling the sim card, neither worked. I'm gonna back up my phone and make a visit to the apple store soon.

I started having the same issue with my phone. First it wouldn't show anything besides "Searching...", and now it cycles between 5 bars with LTE indicator, 5 bars with no LTE, and 1 bar with no LTE. Trying to go to the Cellular page in the Settings app crashes to springboard.

I've tried restarting the phone, reinstalling the sim card, neither worked. I'm gonna back up my phone and make a visit to the apple store soon.

Hit the breaks! KEEP THE LATEST BACKUP YOU HAVE FROM BEFORE THE PROBLEM STARTED. Yes, I was yelling for a reason. Turns out whatever the problem is, it gets embedded in your backup too so doing a wipe and restore doesn't help. It sounds like we had the exact same problem and even the Geniuses at the Apple Store were stumped. No one "had ever seen anything like it." After several troubleshooting/repair attempts, the only thing that worked was doing a flash of the firmware (he called it something like that). It's more hardcore than just the restore you can do in iTunes. Basically returns it to out-of-the-box condition. So here is the rub, when I restore my latest backup, the problem returned. Luckily I had an old backup but it was pretty old. What I did was take the latest, messed up version of my phone (I restored the backup I took pre-Apple Store visit) and took a bunch of screenshots and backed-up everything that I could to the cloud or email (many apps have an email option). Then I went and had them flash the firmware again and the restored the old backup. I used my screenshots and cloud data to configure my phone to basically where it was before the problems. Huge pain, but relatively not terrible given the nuclear option I was looking at having to do... only took a few hours once I knew what approach to take. Also, the Apple Store didn't charge me anything for doing the firmware flashes either time. Good luck man! Let me knowhow it goes if you remember.