You're correct... I am able to install segments of maps from .gmap folder: Western US, Central and Eastern US. Because of the limited memory space, I can only install one of these regions, which is fine for my purpose. I'll transfer others on my notebook and take with me when we travel on our bike.

Yes, you are also correct in the statement that I DON'T understand how this .img works.

My assumption was, since I'm able to copy and paste .img files to my Nuvi and have the map updated, I could also do it with gpsmap 376C...

Assume= "ASS"-"U"- "ME", I was thought in Military. I'm finding out that if I do install these .img files, I will not have the ability to address search, which this unit DON'T have any way.

So, I'll just have to wait til I find a .gmap files to download, so that I can use it to update this unit to newer map. Since my Nuvi's are current with 2015, I have no real need for those outdated .img files taking up disc space in my PC...although I have 2.5Gb in 4HDD's...Thanks guys, appreciate your assistance.

IF anyone know of .gmap download, please do direct me to the site, prefer "kickass" or "the pirate bay" but, other reliable sources are also welcomed.