I just got my bike back from the shop after upgrading my gears from a derallieur to an IGH, plugged in the kit and got Error 21h on my C965 display. The speed sensor light is on which suggests its a problem with the speed sensor wire going into the controller. This will be the third time I have replaced the controller since buying the kit in fall 2016, and the second time for an Error 21h malfunction. The controller is potted so I can't solder the wire back onto the circuit board, I tried doing that before and made a real mess trying to dig out the potting compound. I have a version A pre-April 2016 BBS01 so replacement controllers are getting hard to find (California ebike & EM3EV are out of stock). Not ready to cut off the kit for an all new replacement just yet as the motor, PAS & throttle work, I just get Error 21h and no display.