I just noticed that the published docs have an error, when in standard midi voice mode the mode light is orange (not white as documented, white mode is the arpeggiator). Holding down the mode button changes between the standard and arp modes.
Once a midi controller is plugged in and the mode light is orange - pressing Key 2 repeatedly will cycle through the four allocation modes. Admittedly it is hard to tell which mode you are in without the kind of feedback one normally gets from the arc/grid leds. If I’m lost I usually repeatedly press a note on the controller - if the TR output cycles from top to bottom then you are in the POLY voice mode. Press Key 2 once to get to MONO voice mode.
I have some improvements in the pipeline to the midi modes which should help in this area. In particular I’m trying to work out ways to make the configuration more sticky. On hurdle is naturally the UI…