tl;dr: A new owner of a tiny Xteink X3 e-reader used AI coding assistants (GPT-6 Astra and Claude's Fable 5.1) to debug vertical stripes appearing in greyscale images on the CrossPoint firmware. The investigation uncovered multiple bugs: a broken viewer that skipped the grey "nudge" step, a lookup-table mismatch that made dark grey render as black (also causing chunky text), and stripes likely caused by row-timing variations in the panel's gate driver. Swapping in a longer manufacturer waveform eliminated the stripes and improved shade accuracy, with fixes merged upstream within hours.