Before non-removable battery became mainstream, most phones had a small internal battery to keep the internal clock ticking when the battery is being swapped. This is not unlike the CMOS battery found on PC motherboards.
iPhones does not need this backup power since the battery is always attached. Hence in case the battery becomes completely drained the internal clock will reset. I can't recall what the default time iOS resorts to after a total power loss but IIRC it was a date well into the 2000s.
iPhones does not need this backup power since the battery is always attached. Hence in case the battery becomes completely drained the internal clock will reset. I can't recall what the default time iOS resorts to after a total power loss but IIRC it was a date well into the 2000s.