Some AT&T customers with an iPhone 18 Pro Max said their cellular problems continued after installing iOS 27.0.1, the update AT&T had recommended following a warning about possible service failures, including calls to 911.
What AT&T warned iPhone 18 Pro Max customers
On October 1, AT&T reportedly texted some U.S. iPhone 18 Pro Max customers that their phones might fail to complete calls, texts or cellular-data sessions, including calls to 911. The message recommended installing iOS 27.0.1.
Some users said the update did not restore service
Some affected customers later reported that installing iOS 27.0.1 did not resolve their connection problems. Customer accounts describe failed calls and texts, unusable cellular data, intermittent or persistent service loss, and phones displaying SOS. Other reports describe unaffected phones, including cases where one phone on a household account worked while another had service problems.
The cause of the reported failures remains undetermined
The U.S. iPhone 18 Pro Max is reported to use Qualcomm modem hardware, while versions sold outside the U.S. use Apple C2. That modem difference has not been tied to the reported failures.
