I found this site a few days ago while looking for maps for my valor ddn-868W. I found this thread:
http://www.navitotal.com/showthread.php?9094-Valor-ddn-868w-with-gogo-maps-from-engistech
I downloaded the IGO8 core (and extracted via WINRAR) that chas521 posted from his march 2011 thread referenced in the above thread. I edited the sys.txt file with the suggestions that he made for my screen resolution 800X480, and from post #15 in this thread:
http://www.navitotal.com/showthread.php?7708-Help!-Installing-iGO-8.3-Picture-goes-all-white-and-rolls!/page2&highlight=chas521
I am in the US, so I downloaded ...