Right, I will attempt to answer your many questions and hopefully put my plight into context, equally my eyes are not so young either, in fact last time I looked, I think the date stamp is 1940!!!As for my car which is also my baby and my old age toy, is a very resplendent 2002 Wedge wood blue Rover 75 connoisseur V6, with the well-loved 2.5 Lt petrol engine. Documented mileage of just 45670.Full service history.
Since owning it I have kept it up to date, and as it is in fact a BMW build, I fitted the plugnplay BMW E46 full media unit, which has two dedicated mini-sd slots one for media and the other for GPS (Sat Nav).
As for finding developers, suppliers, etc of mini sd sat nav cards, the web is full of them.Audiotechdirect.com, Senitech Satellite -Face Book, GPS Android sat nav. Satnavishop, and the most obvious one Ebay!
Most based on Sygic and Tom Tom systems. Incidentally all of these suppliers only deal with
Android, which is why 2021/22updates are difficult.(Plus Although they supply sat nav systems via sd cards they do not issue updates!!) Cost of cards between £21 and £39.
My vehicle add on Android media unit BMW E46, came with IGO sat nav on a mini sd card,but I couldn't get on with it, so I obtained the free Sygic system (purchased the further options I required) and its worked well, but its now out of date
Now both Sygic and IGO put out free updates,
IGO is simple,you download the android update, insert your mini sd card into PC remove the out-of-date material from the card, and replace it with updated material. But with Sygic its different, they only download free updates to PC for phones, not ANDROID automotive devices. I have been on to Sygic who were really helpful, but do not issue updates for Android sd cards!
Equally link given by:
mikedt (from China bless him) would only update
devices not sd cards. Also your link ,only explained how to transfer Sygic from internal storage to sd card,but no updates.
So it might be, I return to IGO, as it appears sd card updates for Sygic are not available.