Important Information – Please Read – It may be necessary to convert some maps. Some maps are very large and the memory available on the device may not be enough to load the map causing a memory error message. If this occurs, use the Img2Ozf (link above) to convert the map. Our ‘OZF4’ format only requires a small memory requirement when loaded. The program ‘Img2Ozf’ (Version 3.15 or later) has a ‘Copy Maps to Device’ feature and can be used to copy maps to the device or Memory Card reader. (See the Img2Ozf program help for instructions on configuring Img2Ozf for your device connection type). Img2Ozf Information Page Please Note : when you copy the map image (.ozf2, .ozfx3, .ozf4 or .ecw) to your device, you must also copy the (.map) file for the map image. The map file can be created two ways using the PC OziExplorer. Both options are items on the File Menu of OziExplorer. Source.