I haven’t been able to find this info yet- My expression pedal and aux switch are working fine with the H9. The issue I’m having is the heel position is 100 and the toe is 0. Is it the cable I’m using (I have tried two and they are the same)? I don’t see a setting to reverse the polarity on the H9 and there’s no expression pedal setting to that either.
The problem you are experiencing is because you are trying to use a TRS expression pedal in [BOTH] or Expression Pedal + Aux mode. This mode requires a TS expression pedal. Check out this video, which explains it clearly. It works the same with H9. It also explains how to make the custom cable you would need to make things work with your Dunlop pedals. Go to 9:50: https://m.youtube.com/watch?v=lfi0sbn5c5Y