I use a start/stop msg , the Boss fc50 can only send prg changes... I created a button that sends a start stop msg and , in the low page I created a pedalboard button, with the sub control I linked the two, then with the learn function on the pedalboard button I push a switch on my Boss. I go to the performance mode but all the pedals of my boss play the start stop, not only the one I selected !!