Apple confirmed that a small number of iPhone 18 Pro Max users on AT&T are facing a service-loss bug leaving devices stuck in SOS mode and unable to make calls. While software updates aim to prevent future issues, users who have already lost cellular signal require full device replacements.
The $1,299 handset, which went on sale two weeks ago, relies on a Qualcomm cellular modem in its U.S. configuration—unlike smaller models in the lineup that utilize Apple’s in-house C2 modem.
Apple Confirms Hardware Defect and Details Device Replacement Process
Affected customers cannot restore their cellular connection through troubleshooting, operating system updates, or remote carrier fixes. Apple confirmed in a statement that devices which have already lost service must be swapped out entirely.
“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 spokesperson, via Bloomberg
Customers dealing with total service loss must visit an Apple Store or an AT&T corporate location, or contact customer support directly to arrange a handset swap. Apple characterized the impacted group as a “small number” of users.
AT&T Alerts Customers While Software Patches Roll Out to Prevent Further Failures
Wireless carrier AT&T issued direct warnings to subscribers regarding connection disruptions that could impact emergency calling capabilities.
“Hi, it’s AT&T. Action needed: An important Apple software update for your iPhone 18 Pro Max is available. Some phones may be unable to complete calls/text/data, including to 911. Update to iOS 27.0.1 immediately — Settings > General > Software Update. Please contact AT&T or Apple if you have questions.”
AT&T, automated customer alert text message
Engineers have deployed preventative measures for owners whose phones still maintain a working connection. The operating system update labeled iOS 27.0.1 is available for immediate installation. An automated carrier settings update is rolling out over a 14-day window. Users who prefer not to wait for the automatic push can manually trigger the carrier download through the device settings.
Qualcomm Modem Architecture Faces Scrutiny After User Complaints
One user on an Apple Support discussion thread noted that text messages arrived with extreme delays even when the status bar displayed four bars of 5G, before abruptly dropping into SOS mode. Another customer on Reddit stated that phone calls became completely impossible despite active Wi-Fi internet access.
The U.S. variant of the iPhone 18 Pro Max utilizes a Qualcomm modem, marking a hardware divergence from international editions and smaller domestic pro models running Apple’s proprietary C2 modem. Has Apple publicly verified whether this architectural difference caused the network dropouts?
