Holding down the hard reset button will reset the units. If, somehow, you have deleted the maps off the SD card you will need to contact mio about getting a replacement. place the memory card into a memory card reader and see what files are present in the /miomaps/maps folder.
The Mio came supplied with a SD Ram card (1GB) that contains the other maps. You need to power off the gps, insert the SDRam card and then power on the GPS and HOLD the power button down for at least 10 seconds. The system should re intialize and off you go.. There is/was a link on mio's home page regarding the C220 and the SD card Pete
You probably found the answer by now but if not, the other states are on an SD card that should have been supplied in the box. Just put in th card and leave it there. You will find all the states.
The C220 comes with an SD card with all the maps. Or an SD card can be created with the included CD
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