17.11.3 had much more reliable lines in the behind-steering-wheel display. But after starting a camping trip, the lines disappeared and no assistance sensors data was showing on the display any more except the parking sensors. A first reboot of the touchscreen fixed it but the next day it happened again and a touchscreen reboot didn't fix it.
How does one reboot the behind steering wheel display? No guesses, please.
I wonder if the high mileage of the camping trip caused it. Maybe logs filled the disk, and/or logs couldn't get to the Mothership due to cell coverage issues in the mountains, and they queued up and filled the disk. But, it has had some connection opportunities, since we ended up in a hotel instead, and had wifi.