To download new maps or to update old ones for your Mediatek GPS device, you can use the Mediatek program. You can find it on the disk that came with the device. After you install the program and plug in your device to the computer, the main interface will allow you to download, update or purchase maps that are compatible with your device. If you don't have the disk anymore, the only way to obtain the program is to contact the developer on the official website.