I've got the same problem. Updated firmware, ran the calibration, and still stuck on 4. I've gotten to 5 by clicking on "D" again, but that was only once and the expression pedal still only recognizes the stomp/button press.
Followup:
I spoke with a customer service rep yesterday. I had already tried all available firmware updates, factory resets, and calibration attempts between each firmware update. The rep said that it sounds like a hardware issue and I'd need to contact the seller (Line6 through Amazon) about a return/replacement (Out of Stock till mid April currently), or send it in for Line6 to repair my current model.
Hope this helps those who are worried that they are just doing something wrong.
