After briefly losing service, iPhone will fail to reconnect to cellular network until restarted

Same. iPhone 6 with iOS 10 and T-mobile carrier update 25.1

This is due to two possible problems. The less likely one being the sim card and the more likely one being that you have the iOS 10 Null. Upon updating there is often a failed line of cellular code Injected. To fix this you must reinstall the os again. This will not lose your data so don't worry. Before you do this please check the error logs...

You have either to turn off WiFi or disable LTE in Cellular->Cellular Data Options. Must reboot after that.
It is a firmware bug which will never be confessed by Apple and fixed. Same as compass bug in 6s which is not fixed for 2 years now.

I can confirm the exact behavior you are experiencing.

My brand new T-Mobile iPhone SE (1 week old) did not have this problem on iOS 9.3.5. It regained its connection to my mobile carrier with no problems before the iOS 10 update.

I too tried all the things (airplane mode, network reset, etc) that you tried. Will not fix it. The only thing that will get my cell phone service back is to power cycle the phone.

This is a real problem for me as I work in a 72 story building (no service in the elevator) and I unfortunately have to enter & exit the building quite a number of times per day.

You did not specify which iPhone model, and which OS version. Can you specify?

Thanks,

-RMT

Same exact issue for me. I upgraded to the new iOS last night, and have been experiencing the same problem repeatedly today (on the elevator, on the subway, on the elevator, back on the subway). each time i have to power down to get connection again.

iPhone SE, MLMA2LL/A

T-Mobile

I have the exact same issue, too.

It's an iPhone 6 that was running fine with 9.3.5 on t-mobile. After the update to iOS 10 the phone now no longer finds a network after the connection is lost (e.g. going into an underground parking garage I have a strong signal, in the garage no signal, but he signal never get's restored when getting out of the garage again). Carrier details are: T-Mobile 25.1, but I also experienced this right after the iOS upgrade to 10 without the carrier settings being applied (yet).

It's super annoying and any ideas to get it fixed are welcome. I already performed a Network Reset which did not cure the issue.

we need a fix, but i'm wondering if we change the carrier setting from 'automatic' to 't-mobile', if that will work.

Ditto on my phone too. Before the update my phone would drift in and out of service in my office. I occasionally would get stuck on E (neither LTE nor 4G). I used to toggle airplane mode a couple times a day. Now once it loses signal it's gone until I reboot. Iphone6 also on 25.1 t-mobile.

I called T-Mobile's technical support and they did acknowledge that they had multiple customers reporting this issue and others already. What they asked me to do is to essentially re-load iOS on the device using iTunes. I did just that and will see if this resolves the issue. Their rational was that some of the earlier iOS upgrades OTA had issue with not upgrading all of the OS. Not sure about that, but we will see.

So far so good, but I also have a really hard time to make my phone disconnect from the network at home (already put it into the microwave.. while it was off for sure. 😁 Thinking that this would block enough of the cell signal, but no luck).

Same problem. T-mobile iPhone 6+. If I loose service must do hard reboot to get carrier back.

Same problem here,

The “airplane mode” trick used to work to regain signal, in fact the phone regained signal by itself after a very long wait, but after updating to iOS 10 nothing seems work, and the only thing that can re-connect to the network is to reboot the phone.

Resetting network settings did not work.

iOS 10.0.1 (14A403)

Carrier: T-Mobile, 25.1

Model: iPhone 6 MG562LL/A

Modem Firmware: 5.24.00

Same problem as described. Tmobile and a 6

Same issue here.

iPhone 6 Plus, T-Mobile 25.1

Is there any workaround available until this issue get fixed?

Same exact issue. iOS 10, T-Mobile, iPhone SE 64gb. Worked fine before iOS 10. I've tried all the tricks too, with no avail. I've reached out to T-Mobile and Apple support tier 2.