In the meantime I've decompiled and fully annoted the firmware for a 510(non rs) v2.0 and once my Besst tool arrives, I'll see if I can pull the existing firmware and do the same/compare. Looks like I should be able to recompile on my own and fix it myself if there isn't a response from Bafang.Normally in US you could set max speed at 28mph. I can't help you. I didn't use bafang go (only BESST tool) and in my country when i modified the motor parameters, max speed limit automatically at 25 km/h. No a problem for me, i use motor only to climb on moutain. Request help from SZZS, or another customer in US who use series M motor, or dado. If you recive an software rev (file.bin). Please share it here.