An unknown percentage of people who have updated their iPhone to Apple’s most recent iOS 12.1.2 software update are apparently plagued with curious issues preventing them from making voice calls over their carrier’s LTE network, as well as sending and receiving texts.

LTE and SMS issues

Customers report being unable to use apps with cellular data while others claim their cellular network is no longer working properly after updating to iOS 12.1.2. One user in particular reported seeing their mobile phone delinked from his iMessage account.

The common thread in all these reports is the same: users are unable to send or receive text messages (SMS/MMS). And while cellular data seems to be working without a hiccup in apps like Safari and with services like iMessage, folks are having issues making or receiving cellular phone calls over their carrier’s LTE network (Voice over LTE or VoLTE calls).

Here’s a temporary solution that has worked for me like a charm.

How to fix SMS and LTE issues with iOS 12.1.2

Because this issue manifests itself when your iPhone with iOS 12.1.2 is connected to a carrier’s LTE network, limiting the device to use LTE for data but not voice should fix this for you.

1) Open the Settings app on your iPhone.

2) Tap Cellular or Mobile Data, depending on your language settings.

3) Be sure that the Cellular Data toggle has been switches to the ON position.

4) Tap Wi-Fi Calling, then disable the feature on this iPhone.

5) Go back, then choose Cellular Data Options from the list.

6) Tap Enable 4G, then choose the option labeled Data Only.

NOTE: You may need to restart your iPhone for the changes to take effect.

Doing so will force your iPhone onto 3G and older 4G networks. This should help resolve the issues in many cases but it may and probably won’t work for all the affected customers. After Apple issues a fix, remember to revisit the aforementioned settings and re-enable the Wi-Fi Calling feature and turn on Voice and Data for 4G networks.

This is just a temporary solution and as such isn’t perfect.

For instance, you may be unable to make voice calls over Wi-Fi networks (if Wi-Fi Calling is enabled) and regular phone calls over a carrier’s cellular network will not use VoLTE, meaning phone calls will take a few seconds to connect and thy won’t sound as crisp as with VoLTE.

iPhone Ringing on Table with Speakerphone

On the plus side, you’ll be able to use SMS/MMS messaging services without disruption, iMessage and all the apps that use cellular data will work perfectly and you will have no issues making or receiving phone calls (aside from lower audio quality).

What’s Apple saying? Not much.

Apple support advises performing a full backup, then reinstalling iOS but that doesn’t seem to help. I am actually one of the affected people. After spending countless hours this holiday season on the phone with my carrier’s support, I was able to get a confirmation from them that there’s indeed a problem with the latest iOS 12.1.2 update that’s causing this.

For what it’s worth, I remember at some point after updating to iOS 12.1.2 seeing a message on my iPhone informing me that new carriers settings are available, which I have installed.

I’m unsure if my carrier (T-Mobile) is simply blaming Apple for this or if the carrier settings update that I have installed could be the culprit, but online reports seem to suggest that this is a problem with iOS 12.1.2 that will be fixed in iOS 12.1.3, currently being tested.

Your take

Either way, this is definitely not a kind of issue that Apple customers should be dealing with during the festive season. Here’s to hoping that they release a fix for these annoying cellular woes sooner than later and restore basic smartphone functionality.

Have you experienced LTE calling or SMS problems after installing iOS 12.1.2?

If so, did my fix help alleviate the problem?

Let us know by leaving a comment below.