As far as I can tell, 6.x does not support radio type T so I can't properly navigate the Phatbox menus via the Audi RNS-E head unit. The feature menu options go from "Select radio type S" to "Randomize all mode".
Past attempts at loading 7.x appeared successful initially. The lights turn on and off as expected, exactly as they do when loading earlier versions. However, when the radio is turned on after loading the firmware it displays "CD 1" but does not play music and does not respond to any input via the head unit. I should mention that this was attempted using the Symphony II that came with my car -- well before I installed RNS-E.
I would be willing to attempt boot logging if you don't mind walking me through it. Your input is appreciated.