Apple has rolled out a replacement program for the iPhone 8 models, under which it will repair devices which have faulty logic boards as a manufacturing defect.
The affected devices experience unexpected restarts, frozen screen, and won't power on, Apple mentioned in its forum. The problem affects a very small percentage of the iPhone 8 devices.
These units were sold between September 2017 and March 2018 in Australia, China, Hong Kong, India, Japan, Macau, New Zealand, and the US. Users can check using the serial number of their device if it is eligible for the repair.