Apple Confirms iPhone 18 Pro Max AT&T Cellular Issues, Affected Devices Require Hardware Replacement

In a statement to 9to5Mac, Apple said:

We have identified an issue affecting a small number of iPhone 18 Pro Max users on the AT&T network that may cause a device to lose service and be unable to make calls. We released iOS 27.0.1 earlier this week and strongly encourage all iPhone 18 Pro Max users to update now, and are also issuing a carrier settings update today. These updates together are meant to help prevent this issue from occurring.

The carrier settings update for the iPhone 18 Pro Max will download automatically over the next 14 days. However, users can manually trigger the download by going to Settings, choosing General, then About. Apple explains that the software updates will help prevent future issues for iPhone 18 Pro Max users on AT&T. The software updates will not restore service on devices that have already lost it. Apple says that iPhone 18 Pro Max users who have already lost service will need a hardware replacement. Those users should contact Apple Support or AT&T, or visit an Apple Store or AT&T location. As we reported this morning, iPhone 18 Pro Max users affected by this problem can’t connect to AT&T’s network for calls, texts, and data. Instead, those users see “SOS” in their iPhone’s status bar. The connectivity issues aren’t impacting every iPhone 18 Pro Max user on AT&T.

I’ve heard from a handful of DF readers about this, and the readers experiencing the problem have all found each other in various forums over the last two weeks. The following all seem to be true:

• It’s only a problem for AT&T customers. No such problems on Verizon or T-Mobile.
• It’s only the 18 Pro Max, not the regular 18 Pro. The salient fact here is that the only iPhone 18 Pro models that use Qualcomm cellular modems, rather than Apple’s own C2 modem, are 18 Pro Max devices in the U.S.. So the problem seems to be something related to the Qualcomm modem and AT&T’s network.
• It is not a problem for all 18 Pro Max devices on AT&T’s network. “A small number” is all Apple will say, but anecdotally it seems clear that it’s not most 18 Pro Max devices on AT&T. But it still seems like many. It’s not exceedingly rare.

Pretty unusual that once a device is affected and loses service, the device must be replaced. Yet, the 27.0.1 iOS update contains a fix (or fixes) that should help devices that haven’t yet lost service from losing service. I’d love to understand how a software update can prevent existing devices from being affected, but a software update cannot restore service to existing devices that have already been affected.

Something else I’m curious about is whether it’s related to AT&T customers, or AT&T’s network — are iPhone 18 Pro Maxes that are connected to MVNO carriers whose backend is provided by AT&T similarly affected? E.g. US Mobile customers on US Mobile’s “Dark Star” service? I’d love to hear from anyone who knows.

★