I was searching and found an easy way to unlock the Nav system on Prius so that destinations etc. can be put while driving. You need to get to Service menu as follows: Press the following combination to get to the service menu of your Prius nav. system. 1. Menu,Volume,top left, bottom left, top left, bottom left Once you see the service screen, press OverRide till it beeps. All done. Go back and back to MAP. Now if you drive the car, all icons will be available. If does not work, repeat again. Have fun.
It works on a 2005 with the original DVD. By the time I got my 2006, they had "upgraded" the software to remove the option. I think it even goes away if you update the map for a 2005.
