You have a newer hardware version of the M600. You won't upload old software versions to it, i.e. 14.6 for example. For the new hardware version there is 46.3 and 46.2 as far as I know. Unless there are some more then someone please correct me.Besst tool received with a dealer login so I have tried the modified 46.3 firmware. It is certainy changed from the default 46.3. L1 power is now good with maximum 100w output, ideal for low power use on flat trails to conserve battery. L5 was full power but will need to test on my local hill climb to check how it responds to cadence and torque input. Will be interesting to compare to 14.6 which is my preferred FW so far. I have downloaded 14.6 from Github file library but for some reason it will not load using the update function on Besst. I select it ok but it seems to fail a compatibility test and wont upload to the Besst box. Does anyone have an original Bafang version of 14.6?