Have built OpenScan Mini using Pi 3 B+ and installed updated software. I can connect via browser to the UI, and switched to the simplified UI. Everything works (camera, ringlight, ...), except for the two stepper motors or drivers. I think the Rotor stepper is getting some kind of signal - it holds position when powered on, and clicks when I push the buttons on the Scan screen, but doesn't seem to move. However the turntable stepper won't hold position (it spins easily if I move it) and it doesn't even twitch when I hit the buttons on the UI. So, is there a way to connect to the Raspberry Pi and send/monitor the low level signals to the A4988's? Both are connected, their Vref's are currently set to limit stepper current to about 0.75 A (Rs on these is 0.1 ohm, and Vref's are set to 0.6). Basically, I want to verify that the stepper drivers are being told to do the right things, somehow. Anyone who had a similar problem?