Apple has told reporters that a small number of iPhone 18 Pro Max units on AT&T cannot be rescued with a software update once cellular service fails. Calls, texts, and data drop, and those phones need a replacement already running iOS 27.0.1 plus the latest AT&T carrier settings. The company says it has only seen the failure on U.S. Pro Max models, which use Qualcomm’s Snapdragon X80, while other regions ship Apple’s C2 modem. Apple has not confirmed the modem is the cause. Owners who are not affected should install iOS 27.0.1 now.