Had some fun debugging the other day. QA reports bug by interacting with UI. Debugging whole SW stack down to HW level didn’t bring any definite conclusion so the day was saved by electro guy with osciloscope.
I’ve never watched anyone using osciloscope to debug communication issues so it was very interesting to watch. Modern osciloscopes have options to set baudrate and decode options so you can get to data payload directly from wire bypassing anything related to SW side of things.
In the end it turned out to be a HW bug. And gate was nulling response from device.