Thread: How To Get Your SD Card ID in Your Garmin Device

Originally Posted by platonikus

Why is this number so important?

This number may or may not be important depending on what you are trying to do. Thes days, it's relatively unimportant for most folks.

This number (the SD serial number) is necessary only if you have a situation where you are trying to generate and Unlock key for a map saved on a specifc SD Card and you would like to use that particular SD in mltiple GPS units.

In a keygen (generating an unlock key), using that SD card S/N associtaes the MAP, the Unlock Key/code, and SD as a "set" so the map is now unlocked "only" on that SD and you can then use the SD and Map in any GPS you like.

If on the other hand you were put a map on SD and create and Unlock Key using your GPS Unit ID (as opposed to the SD card ID), the map would only be unlocked when the SD containing the map was used with the GPS for which it has been unlocked.

Although are still a few reasons for wanting to still use an .UNL file containing a key, these days, it's generally much easier to simply use an unlockable IMG files as they work almost all cases with all devices.