Quite annoying this one, I have a Desire running Froyo, when I'm using the Google Nav the phone tends to get very hot and (i assume) that upon reaching a certain temperature shuts down and re boots. Usually just when I'm totally lost! If i hold the phone in front of a vent with the air conditioning on to cool down its fine again, if i don't then once the nav is restarted it will shut down the phone again. The air conditioning trick isn't the answer as i have to sit in a freezing cold car in the middle of winter in order to use my sat nav. Is this a fault? Would taking it back and getting a new one help??