Thread: Nuvi 58LMT "can't unlock maps".

Yes I removed all the old GMA/UNL files.

I also tried removing the new ones so it had no detail maps at all. Powering up and I no longer get the warnings but of course no usable detail maps.

I then let Garmin Express recreate the files by reinstalling maps. Warnings and errors back on power up.

I tried replacing those files with the ones from a "clone" SD card which GE had created maps on, same warning.

I've copied the newly created files from the device, SD and older back up and compared. The large *.img files are identical (same hash) but the .gma/.unl don't match. Presumably that's expected?

I am wondering if the unlock algorithm changed in some way that's incompatible with older devices: this one is from 2017.

If there are any diagnostics or other things I can try let me know. I'm pretty tech savvy but a noob when it comes to Garmin internals