does it still say autodetecting gps? is your time/date wrong
This morning when it happened, I hadn't tried the hard reset, so the clock was still accurate from yesterday when it was still able to 'see' the GPS hardware. It did say "autodetecting gps receiver" my entire commute in, and when I dug into the settings of the GPS, I remember the first line said something like "GPS Status" and the status was "NOK" (assuming to mean NOT OK).
Got to work, turned off the ignition. Start the car back and and everything seemed ok. It said "searching for GPS signal" at the top instead of "autodetecting gps receiver" but I was in the parking deck so that made sense.
.....
OK just went out for lunch and the radio is operating normally. GPS fully functional now. Still worried that if it randomly happened 4 days post-install, that it could happen in another 4 days, a week, whenever!