you need a manual change to /root/Bela/pru/pru_rtaudio_irq.p
to enable the muxer with CTAG beast: you need to ssh onto the board and open the file in an editor, find the line
//#define ENABLE_MUXER // enables run-time selection of the Multiplexer capelet
and remove the leading //
, so to uncomment the line.
If you confirm this works, I can then apply this change on the mainline repo so that you won't need to apply this change again next time you update your board.
you need to ssh onto the board and open the file in an editor
if you don't know how to do this, you can ask again and I'll guide you through that or a simpler alternative.