I attempted upgrading my Ender 3 firmware to Marlin 1.1.9, and due to inability to find the directions about the Sanguino variant pin layout file, stupidly built with the "standard" (Arduino) file. Various stuff didn't work, and I figured out my mistake and rebuilt, but the extruder motor does not respond even after flashing back to the original firmware.
Did I destroy the stepper driver with incorrect pin mapping? (Aside: if so, why just the extruder and not the others?) Is this fixable or should I just order a new motherboard?