When setting the VREF on the DRV8825 is it possible to accomplish this while the driver is plugged into the driver control board that is supplying 2.5 to 5.2 to the logic as long as the VMOT is not supplied? Or do they have to be wired on a bread board as in your instruction video?
You can probably set the current limit with the DRV8825 installed on your driver control board. However, you would need to have VMOT and GND connected to set the current limit. I suggest disconnecting your stepper motor while setting the current limit like this, so you do not damage the stepper motor in case your initial VREF settings are too high.