That implies changing motor's mode from SpreadCycle into StealtMode (or vice versa)
requires a stand still MMU with no other command (i.e. motor moves) being performed.
This elegantly solves the synchronization problem of TMC2130 mode change, as it results
in severe jerking while a motor is moving.
The change in protocol is minimal - M0/M1 first return `M0 A` (accepted) and another `Q0` then
returns `M0 F` (finished). The MK4 counterpart may ignore the additional report if necessary
as the mode change is done immediately (shortly after responding with `M0 A`)
D.R.racer