[Windows]USB Midi Device Not Recognized After CB8 Is Running

Most of my MIDI gear is connected with traditional MIDI cables to USB-powered MIDI interfaces (Motu midi express 128 and Steinberg Midex8). So they are always connected when I switch them on.
However last week I got me a new synthesizer module, a Yamaha Motif rack XS, and I want to use the Editor vst plugin. For that I need direct USB connection, but this fails when the unit is not switched on before Cubase startup.
The unit can be expanded with a (FW16E) FireWire Expansion for audio and MIDI.
Does anyone know if the firewire does connect after Cubase startup?
I’m asking because I think it’s possible: my firewire audio interface (Steinberg MR816x) DOES reconnect after switching off and on with Cubase opened, and also my Motu midi express is reconnecting, which makes me think it’s a driver issue?
I started a topic in the Yamaha synth forum, but didn’t figure it out yet: