Apple: already-dead AT&T iPhone 18 Pro Max units need hardware replacement

Apple has confirmed that some iPhone 18 Pro Max devices on AT&T that have already lost cellular service need a hardware replacement. Software and carrier updates will not bring those phones back online. They are meant to help stop the issue from hitting more customers.

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."

Apple told 9to5Mac that phones that have already lost service will not regain it from those updates. Affected owners should contact Apple Support or AT&T, or visit an Apple Store or AT&T location for a hardware replacement. AppleInsider reports the same guidance: already-impacted units need to be replaced.

What affected phones look like

Owners who hit the bug cannot use AT&T for calls, texts, or data. Many see SOS in the status bar instead of normal signal. The problem has not hit every iPhone 18 Pro Max on AT&T, and Apple still describes the population as a "small number" of users.

Prevention path: iOS 27.0.1 + AT&T carrier settings

Apple released iOS 27.0.1 earlier in the week and, on October 2, pushed a matching AT&T carrier settings update. MacRumors identified the carrier package as version 72.1 (up from 72.0.2) and noted that Apple also began requiring iOS 27.0.1 during iPhone 18 Pro Max setup.

The carrier update can download automatically over about 14 days. To check for it sooner:

1. Open Settings
2. Tap General
3. Tap About
4. Wait for any carrier settings prompt, then install it

Neither update restores service on a phone that has already dropped off the network. They are preventive for units that still connect normally.

Qualcomm modem context

In the United States, iPhone 18 Pro Max uses a Qualcomm modem. The smaller iPhone 18 Pro, which uses Apple's C2 modem, is not affected by these AT&T connectivity failures, according to 9to5Mac. Apple has not published a detailed root-cause explanation tying the issue to a specific modem part.

What to do next

• Still connected on AT&T: Install iOS 27.0.1 if you have not already, then open Settings → General → About to pull the AT&T carrier settings update.
• Already stuck on SOS / no cellular: Contact Apple Support or AT&T, or go to an Apple Store or AT&T location and ask about hardware replacement. Do not expect the software path alone to revive the device.

Apple and AT&T have not said how long replacements will take or whether a broader service program will follow. For now, the company's public line is clear: prevention for everyone else, hardware swap for phones that already lost service.

:::poll{id="91d5db90-d4f6-42ec-89a5-7f542e2018c9"} If your AT&T iPhone 18 Pro Max lost cellular and showed SOS, what would you do first?

• Book an Apple Store or AT&T hardware replacement right away
• Install iOS 27.0.1 and the carrier settings update, then wait
• Contact Apple Support or AT&T Support before visiting a store
• Hold off until Apple or AT&T publish more details :::

Sources: 9to5Mac, AppleInsider, MacRumors