Hi, I built a MUZZLE and I have the same problem as you on key input. when i make a jumper between key 1 and key 2 the pedal works. on the other hand when I cable the jack sold by muzkding it does not work in several connection possible. if you can send me the pictures of your connection this could help me.
thanks pedal pcb yesterday i got a special overdrive kit via muzikding in germany i would ask you can you send me the photo of the finished pedal if you have a special overdrive that can put together the post amateur friendly greeting Harry