In April 2012 Nophead from HydraRaptor fame, brought us the micro-current hack for the pololu 4988 stepper motor driver carrier. http://hydraraptor.blogspot.com/2012/04/stepstuck.html
Now, it is my turn…
The amazing DRV8825 driver carrier has a similar flaw, strange jumping of steps in 32th micro-stepping mode.
After doing a bit of research, it seems that we need to put the chip in FAST decay mode, by pulling the DECAY line of the chip to 5V. Luckily the DRV has exposed pins, so I carefully soldered the DECAY pin (19) to the M2 pin on the board (will be 5V when 32th uStepping is enabled.)
Movement as smooth as butter!