Apple is urging certain iPhone 8 owners to turn in their phones for repairs, saying that some devices may experience frozen screens and unexpected restarts or won't power on.

The devices suffer from a defective logic board, the company said on its support page, and were made between September 2017 and March 2018 in Australia, China, Hong Kong, India, Japan, Macau, New Zealand and the United States. Only a “very small percentage” of iPhone 8 devices were affected, Apple said.

Customers who think their phone may be defective can check Apple's support page to see if their device is eligible for a replacement. Apple said it will repair the phones for free.

The support page instructs customers affected by the defect to find an authorized service provider, make an appointment at an Apple store or arrange a mail-in service. The iPhone 8 Plus and other iPhone models are not affected by the issue, Apple said.

Apple has offered to replace faulty parts in its two earlier smartphone models, the iPhone 7 and 6. “A small percentage” of iPhone 7 devices contained a defective component causing the phone to display “No Service” in the status bar even if cellular reception was available. And Apple swapped out batteries for a “very small number of iPhone 6" devices after the affected phones unexpectedly shutdown.