Nuvi 200 firmware update "on the fly"??

 

I was driving along today when my Nuvi 200 beeped - I looked at it, and there on the screen was a box with a message saying "Updating GPS Firmware". A counter then ran from 0% up to 100%, and the box closed. The Nuvi then reacquired satellites and continued to navigate as it had been doing before. What happened? I don't believe there is any way the Nuvi can update its firmware when it's in my car, not connected to anything except the cigarette lighter socket. Has anyone else had this happen to them?

(When I got home, I checked and it still had the 4.10 firmware it had before, so I went ahead and used Webupdater to update it to 4.30, since that was available.)

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"Recalculating... drive 0.2 miles, then abandon vehicle." ------------- [ETrex Venture CX; Nüvi 40; Drive 52]