Had this issue on my 2014 Dodge Journey. The screen turned black, and then the next time it turned on, no detailed maps... I asked the dealer about it and the guy had heard about it and said the only fix was to replace the stereo. That didn't sound right. It took a lot of searching to find all files, but finally found them all (and upgraded to the 2018 maps). I couldn't do the one step update (got half way then failed, but the multiple step worked). I left the 5 files in the main folder and the SQLite folder (unsure if that helps, or if I have anything extra, but it all worked). Here were my steps (PM me if you need an help with files):
DOWNGRADE TO CTP13
Downgrade radio navigation to CTP13! This is very important as newer versions have securIty that prevents loading of maps without dealer codes. Take a second USB drive with the gupdate.gcd from CTP13. Turn on the car and hold temp up + temp down + front defrost, after a few seconds dealer mode will pop up. Select garmin recovery update and plug in the usb drive with CTP13 on it. NOTE: After you flash this it takes a long time to load. Let it load and it will still say cannot unlock maps. Just click ok, you may need to restart your car one time to click out of the pop up.
RESTORE MAPS (LONGER VERSION, SHORT VERSION DIDN’T WORK)
1) On the USB stick, create another folder in the root named "Disabled".
2) Move the Garmin subfolders (ASR, JCV, & SID) into the "Disabled" folder. Keep the five files (gmapprom.img, gmap3d.img, gmaptz.img, gmapbmap.img and gmapdem.img) and the SQLite folder in the Garmin folder.
3) Plug the USB stick into the car and perform the update. It will take about one hour. You don’t have to keep the vehicle running but rather in the ON position. The vehicle will turn off after 30 minutes, so do a cycle before that time (don’t start the vehicle as it will turn the system on and off again).
1) On the USB stick, move gmap3d.img, gmaptz.img, gmapbmap.img and gmapdem.img from the Garmin folder into the Disabled folder. Leave only gmapprom.img in the Garmin folder.
2) Move the JCV folder from the Disabled folder into the Garmin folder (SQLite Folder stays).
3) Plug the USB stick into the car and perform the update again.
When this is done, the Junction View is now installed, and the 3D landmarks and time zones are still there.
1) On the USB stick, move the ASR and SID folders from the Disabled folder into the Garmin folder. Leave gmapprom.img and the JCV and SQLite folders.
2) Plug the USB stick into the car and perform the update once again. After this is completed, the system is fully updated to the new maps and all features work except for the phone number lookup.
Using the latest files from https://www.driveuconnect.com/support/software-update.html upgrade the radio and GPS software. In September 2018, these files were: CTPMY14.KWI (Radio to 7.09) and gupdate.gcd (CTP17). The first is the only file in the root directory of the flash drive. The second is the only file in the Garmin folder (no other folders or files on the drive). Do one and then the other.