I connect norns to axoloty via a MIDI interface, and then axoloty to other devices via USB host or USB device. That’s because I need to use the axoloty USB port with other devices, eg Organelle or my laptop
you should build a patch/patcher using
MidiSend3((midi_device_t) MIDI_DEVICE_DIN, 1, status, data1, data2);
MidiSend3((midi_device_t) MIDI_DEVICE_USB_HOST, 1, status, data1, data2);
MidiSend3((midi_device_t) MIDI_DEVICE_USB_DEVICE, 1, status, data1, data2);
for details, search in axoloty forum 