I assume know known change around when you started getting the error.
I assume you have also power cycled the board.
Schematic is here
I assume you have at least a volt meter. The board has a couple marked
ground pads to can use to measure to.
Measure the voltage on the write line U2 16. It should be > 3V.
If not check at RN1 which pulls the signal high. Pin 1 is 3.3V and pin 4 is
the write line.
If that was high check U2-4. If its low check that pin 19 is low which
If its high check on P9-31. If that is high it seems to be a problem
with the beaglebone.
The other signal the error refers to is E_STEP.