If I was the developer, then I would figure out that a timestamp can never be older than the device itself (if you buy a TomTom today, it will never receive dates from Jan 2019 or earlier, so we can just use a window and hope the device doesn't last for 1023 weeks :-) Probably changing the ROMs going into manufacturing once ever year or even every five years is fine.
But even without this, you'd only get into trouble if some satellites are in week 1023 and others in the next week (week 1024 but transmitted as 0). But that state lasts for less than a tenth of a second.
Biting the hand that feeds IT
