I spent 20 miles on a non existent Japanese road yesterday. The cars satnav was issuing intense instructions to turn right as one approached a T junction according to cars Satnav, but the road ahead was open, swapped to Google Maps got a Japanese data SIM, also have a track running on my other device. I love to navigate more easy than driving

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Back to Seat. Yes the SD map cards are modified ones with a data area not normaly found on SD cards that contains the card's ID that's registered to the car. In the installation process this happens. Changing the data on the card via those Mapcare download sites means that the bit of data that isn't written normally doesn't tally with what has been written so it doesn't work. If it did, those in Europe who hadn't paid for Mapcare would get free upgrades.
So that leaves the question of why some people got their complete new eBay cards to work and others didn't. It seemed the cars software that the unit was running under was different. That's my praisy of the long thread you may find elsewhere covering the Leon Mk3 owners in the UK trying to use the Mapcare download site and their experience of how they got on buying the new ebay cards.
So really anyone kicking off on this needs to know the head ends software and year of the map file release. Early days for the Ateca on this. I think you could moan if you were sold a car with an old map file SD card. The German board was talking about the serial number of the map files. A number of owners got there cars less the SD card.
Haven't got my car yet and mine will be a Navigation Plus so upgrade routes are different. Owners of the standard system could usefully post up their details perhaps if they felt diddled. You do a key combination to read off the details.... I will be checking mine when I get my car.