You should use an actual basemap, not a detail map named as gmapbmap.img, if that's what you tried. If you want a small basemap use the latest V5.1 with DEM stripped out with GMapTool. However, this is seeming like fw to me. If voices work on simulation, why not in actual navigation if you don't have FM transmitter activated? Seems odd, and not a usual problem. Reset the unit, reload the current fw, reset again.