Garmin Navigator 2018.20 maps, released 05/18/2017 Current as of 07/26/2017
CN North America NT 2018.20 Lower 49 States Does not include Alaska, Hawaii, Canada, or Mexico. Only the mainland US.
Works on my 255w, and should work on all older units that don't check for cracked maps
Some devices only work with older non SDHC SD cards, 4GB-8GB in size. If it doesn't work, try a smaller SD card.
If your Garmin has enough internal space: Rename gmapsupp.img to gmapprom.img and replace it with the one that is on the internal memory.
If your Garmin doesn't have enough internal space, or you don't want to delete the original maps:
- Format an SD card as FAT32
- Make a folder on the SD card called "Garmin" (without the quotation marks)
- Copy gmapsupp.img to the Garmin folder on the SD card
Once the unlocked maps are on your device, and the SD card is inserted, turn the device on and make sure the new maps are selected under Tools>Settings>Map>Map Info