How to Unlock Garmin Maps

For years I’ve held off on publishing a step-by-step guide on how to unlock Garmin maps because I didn’t want to encourage software piracy.  However, I like to have a backup of my route and Garmin maps on the SD card in my device just in case of a glitch.  For cyclists that have a legitimate reason for unlocking their Garmin maps, this guide is for you.

Caution – Do not attempt this unless you fully understand the process and your computer is fully protected from virus and malware.    

  1. Create a Garman folder on an SD card
  2. Locate gimgunlock.exe on the internet and download it into the Garmin folder on the SD card.
  3. Locate the file gmapprom.img on your Garmin device and copy it into the Garmin folder on the SD card.
  4. Drag and drop the gmapprom.img onto gimgunlock.exe to unlock the maps.
  5.  Rename gmapprom.img to gmapsupp.img on the SD card.
  6.  Test the SD card to ensure that the files are in fact unlocked.

If you are considering using this method to pirate maps from Garmin without paying for them, DON’T!  It simply isn’t worth it considering how costly a mistake can be. Especially when you can buy legitimate maps for just $19.99.  Check it out at Cycle Map North America at

Ken Whittaker