i recently got a magellan gps for 12 dollars at a thrift store and i cannot get the usb mode to work on my computer as it has driver problems and after messing around i found 3 menus. a shell menu (hidden menu),a diagnostic menu? and an sd card boot "menu" i i tried many sd cards of many sizes and i can't get the menu to read the sd cards but one a lexar 4gb sd card behaves differently. Instead of saying "SD card boot please wait... waiting!!" it says "SD card boot please wait..." if someone can tell me what im doing wrong or what sd card i should be using that would be great GPS Model is Magellan RoadMate 2200T