Thanks. Yeah, I got in the way. Before I went through the lengthy download process, aaagain, I copied all the files inside the folder and pasted them outside the folder onto the SD card: put the SD card back in the car and started it, Voila! it performed the update flawlessly, and probably quicker than ever: I bet it only took a tad over twenty minutes.
The only hitch was that my cellphone was no longer paired. But when I went for a walk and started the car, everything was back in order: called my wife with the voice command, and she called me back and I answered with the phone button on the steering wheel.
What the heck is that "Black" option for map color? It's like perpetual night. What's the point?