Sama-sama, selalu senang membantu tetangga. Salam dari Australia!

That's a good result, i assume you didn't need to re-format the internal memory. after you've replaced files with GarminExpress you may have to copy a basemap manually into the .System folder. The one from your backup should be safe to use, look for gmapbmap.img in there. It's very unlikely it was the problem being as it's the original basemap from the factory.

If you'd rather use an 'known-good' basemap just let me know and i'll upload one for you. Without a basemap navigation may fail and zooming out on the map screen might cause the 3790V to freeze, crash or spontaneously reboot.