Neil, it did not work.
I unlocked the 'gmapprom.img file using gimgunlock, and renamed it to gmapsupp.img and put it in the folder 'Garmin' on the device.
Unplugged the device from the PC and turned it on. However, when I went to settings > Map & Vehicle > myMaps I don't see the Indonesia map installed.
Is it because of the simple fact I did not use a microSD card? or is there something I did wrong?
Am I also to copy the JVC file along with gmapsupp.img file?