Hi -
I'm still working to track down whether or not the driver supports Speaker Fill. In regards to the problem where setting to 5.1 audio does not stick - I was not able to reproduce that here on a 5.1 setup. Configuring and saving for 5.1 'sticks' after rebooting and power cycling the system. I didn't have the same model setup as you however. Do you have access to any other 5.1 system anywhere that you could plug your NUC into and see what happens?
Regards,
Lois H.
Intel