I had a dead Biktrix headlight after replacing the wiring harness. Problem was that the headlight has a required polarity since its lamp is an LED. The "+" and "-" for the prongs are nearly invisible, and the leads are only sort of color coded (black and a vague rust colored smear). Reversing the leads fixed the headlight.
Otherwise, the Eggrider is a great improvement over the Bafang display. You want to play with all the motor's programmable parameters? You can do it on the road or trail using your smartphone and the Eggrider app. If you are really bold, you can do it while riding. I'm not that reckless. I stop to adjust things.