I have been using for almost a year but forgot to mention in this thread, a MT-32 Pi variant, namely the BulkyMIDI-32 with success under every supported midi software I have tested (from playmidi cli command to scummvm and audio software under MorphOS such as Horny etc). Tested under MorphOS version 3.17 and 3.18 with a Roland UM-ONE usb-midi cable (had issues with cheap cables, whereas Tcheko didn't in his setup using the very same cable). I am also using a privately build native version of RaspMIDI which I hope Tolkien finally releases into the public :)