In manual mode "M", automatic downshifting only occurs if the engine rpms become too low. There is no automatic upshifting in "M" mode; the rider must always shift up themselves. In automated shift mode "D", downshifts and upshifts are automatic, but the rider can override / manually select the desired gear via the foot gearshift lever.
When riding downhill in manual mode "M", the braking torque/engine speed (throttle grip/brake) is regulated or, in transmission mode "D", the system automatically shifts according to the throttle grip/engine speed depending on the riding mode.
For the best possible utilization of engine braking , e.g., when descending mountain passes, it is best to select manual mode "M".
Link to watch video: Automated Shift Assistant - Manual
