Updating Maps on Micro SD card

You state you have an SD card with US maps and want to know if the maps on the SD can be updated. If this is the case, the answer then is DEPENDS.

It will depend if the card is from Garmin, if so, the answer is no, the card cannot be updated. That doesn't mean you couldn't overwrite the locked maps but Garmin would require the purchase of a new card if you want only the US maps that would then work in any unit.

You do have other options, that being purchasing a lifetime map update or switching to Open Street Maps. Open Street Maps can probably be loaded to your SD card and they're free. You do lose a lot of Garmin features, speed limits, Junction Views and POI along with other things built into the Garmin maps. As has been stated in many other threads, an add-on LM purchase will allow the maps to be put on an external card, but the maps are locked to the unit not the card.

A couple more thoughts on Box Car's reply--as always, correct me if I'm wrong:

1) If the current nuvi 52LM is a UK/Ireland device, adding lifetime North America maps requires two things: buying an original City Navigator NANT map on a DVD, then buying the numaps lifetime North America update. This will most likely cost more than buying an entirely new North America-mapped nuvi with lifetime maps. The numaps lifetime North America map update can't be installed to a device that doesn't have a North America map already.(I feel 98% sure of this)

2) (I may only feel 70% sure of this) I think I've read that when adding a 2nd continent; e.g., adding North America to an original European-mapped nuvi, that you will not receive features like Junction View for the 2nd added map. If true, this amplifies the thought that the best and probably cheapest way to have a Garmin City Nav North America device with lifetime maps is to buy a new North American-mapped nuviLM(T) rather than to add a North America to a European model.

I'll admit I'm clueless on this but I wonder if the SD card (assuming it's the Garmin card) would take the place of the DVD? The card, being able to go into any unit would have all the needed files to display whatever the unit allowed. You almost have to assume it would have the JV file as Garmin wouldn't have different cards for each of the 3 series, the Essential, Advanced and Prestige.

I see two possibilities:

1) Garmin's software accepts the North America on SD and allows a numaps lifetime subscription to work. If Garmin is generous, they'd say "I see the North America on the SD that the person bought and will allow the lifetime update to activate."

2) Garmin's software doesn't accept the SD-card North America map and reasons "once we allow a numaps lifetime update to apply to the nuvi, the owner could sell the Garmin SD-North America on eBay--or any owner of a European-mapped nuvi could buy a used North America on SD, get the numaps North America lifetime update applied, then resell the SD card map."

Being a natural pessimist/realist, I'd bet on #2.

Worst case scenario: you need both. Currently Amazon offers:

City Nav NANT DVD: $58
numaps lifetime CNNANT update: $67
Total: $125 to add the US to a European nuvi.

A brand new nuvi 52LM with lifetime US maps: $100 (or $132 with North America instead of US)

...or, as Garmin sees things:

https://support.garmin.com/support/searchSupport/case.faces?...

microSD™/SD™ card Requirements

Please note, these full-version maps do not contain premium content such as junction view or 3-D buildings and terrain. These features only are available on the preloaded maps within your device or through a specific update for the mapping region of your device.

A bit more info on multiple maps and multiple JVs, although you need to remember that the thread below refers to two maps' JVs where both maps are for the same continent and may probably not apply to dual NA/UK-Ireland maps and JVs:

http://www.poi-factory.com/node/40535

Long story short, Hawkslayer: in my opinion your best option is to buy a new nuvi with US or North American lifetime maps--or add the open source routable Garmin-compatible maps as Box Car pointed out earlier. You will most likely not be happy trying to add the Garmin US or North American maps with lifetime updates to your UK/Ireland nuvi.

There's nothing stopping you from reselling the DVD either.

Thanks for all the suggestions guys, I guess from reading them all, that the best way to go is to get a new GPS with US maps. I found a special deal on a Garmin 3580LMT with free Traffic and Lifetime map updates, so I have ordered one of those. Of course I'll save the 52LM with the UK and Ireland maps and keep it updated, in case I get to go over there again. Thanks to everybody for commenting.

Hawkslayer...