I found the solution.
I could not use the img file that came installed on the GPS. I had to use the map updater and install City Navigator directly to my hard drive.
Once on my hard drive, I created/selected the mapset in mapsource and sent the mapset as gmapsupp.img to my hard drive.
I was able to unlock this file with FIU (no truncation) and it was successfully sent to the Etrex Legend HCX and appears to be working well.
FIU = nice little program.