I'm not sure of how you get the CID by using diagnostics mode on a 1490T. For a nüvi 3790T you will have the 3rd page in diagnostics ""Data Card Test Page" and the "Serial" value. Skip everything about checksum in diagnostics since it's not needed and just takes a lot of vasted time.
Be sure to use JM KG v1.5 with Checksum-fix. Otherwise it will generate wrong keys near 2048=2*2^10 (2043 is close enough and old KGs gives unvalid keys). It should work with [X]:\Map\gbdisc50kv2.img and [X]:\Map\gbdisc50kv2.unl if the key inside the UNL-file is generated with the right KG, UnitID or CID and MapID.
I will send a PM with a 25-char key for your unit.
Bookmarks