at http://elinux.org/Beagleboard:Cape_Expansion_Headers#Full_Headers_with_8_Modes the pinout of expansion headers is shown. For every pin there is exactly one row describing the functionality of the related pin according to a chosen mode.
But pins 41 and 42 of header P9 are different, they are named “41#” and “42@” and contain two rows describing possible functionalities and two GPIOs each. So…what does this mean? How can one choose a specific functionality of these pins? Setting the pin-mux-mode doesn’t seem to do the trick since it can be used with the standard modes only and here twice as much are listed.