[Shark413]

I had a similar situation. I successfully updated the firmware on my MMM installed in my buggy. When I went to update the MMM in my truggy, the software would initially see the ESC then while updating it would get the "no response from controller" message. I tried unplugging replugging the USB cable with same results. I then figured maybe the USB Castle link was the problem, since I had three of them I plugged in another one and tried updating the fireware again. Success, it worked. So if you can try a different Castle link USB module.