I have a related problem. When I switch on my M5 Stompbox, I am unable to change from one 'Model' to another, using the Model Select button.... it just stay on the same model.
I figured it might be worth doing a factory reset, but I would have to go through the steps described above, and I can't do that because the 'Model Select' button doesn't work!
It's probably a hardware (button) fault, in which the factory reset is unlikely to work, but I thought it was worth a try.
Has anyone else suffered from a non-working 'Model Select' button?