I confirmed that pushing the volume button and holding for nearly 30 seconds did reboot the Uconnect, it clearly showed the startup screen etc. The two hand push both buttons worked faster but it just shut off, came back to the screen that it was on.
For the visual learners the reset info (its' brutal to describe going through menus and buttons on a screen)
Vehicle Menu
View attachment 1391
Tap reset to get to another screen, it doesn't go straight to reset ! The Uconnect restart is the first option
View attachment 1392
Bottom of that menu is the full reset, clears all the settings. I did this this AM, This was also reported to somehow awaken the Drag and or Track modes in the updated cars.
View attachment 1393
Enjoy