Also be aware that the version of ttyMIDI we use for processing the DIN-5 connections does not support sysex. (We could modify it if necessary but as it stands - no sysex.) ttyMIDI also converts note-on with zero velocity to explicit note-off (with velocity 64) and converts running status messages to full MIDI commands. This is all to simplify downstream code but is not necessary in Zynthian (or any other JACK based system) so there are many improvments that could be applied.