Apple has determined that a small number of iPhone 8 devices contain logic boards with a manufacturing defect. Phones affected with the problem may experience unexpected restarts, a frozen screen, or won’t turn on. To resolve this issue, the company has implemented a logic board replacement program, which is free of charge.

Units affected were sold between September 2017 and March 2018 in Australia, China, Hong Kong, India, Japan, Macau, New Zealand, and the United States. To determine whether your phone is eligible for a replacement, you’re encouraged to use the serial number checker on the replacement program website. The issue doesn’t affect the iPhone 8 Plus or other iPhone models.

If your handset qualifies for a free replacement, you can receive maintenance at an Apple Authorized Service Provider or Apple Retail Store. You can also contact Apple Support to use the company’s mail-in repair service.

The iPhone 8 was announced and released last September alongside the iPhone 8 Plus and iPhone X.