Just posting this so that someone may find it if the same bug pops up again.... Had my annual service done on Wednesday and went to collect the car on Thursday. Service included swapping out for a new 12v but when I went to drive home I noticed that the Alpine NAV-10 didn't power up at all. Went back in to the service center and by holding down the power button we did eventually get it to boot but all unit controls were frozen, the screen was unresponsive and unreactive to the remote. Searched TMC and couldn't find it had happened before. John at Tampa Service (thanks John!) checked out the battery and power supply and found it all ok; pulling fuses and replacing them didn't seem to make any difference. Next he removed the left waterfall trim inside the car (Roadster 2.5) and one by one reset each of the control units in there (nav, sirius etc.), that fixed the issue. Music, nav, satellite all working again and all my original settings were still there.