SCREEN 13 works, SCRTEST passes end to end, palette cycling is smooth, and as a bonus the fix also killed a stack-vs-bss collision that was waiting to happen. wrote AURORA.BAS to celebrate, it does a starfield and a sine curtain with the classic palette-cycling trick so it stays fast even interpreted. next up (probs): making it the boot splash, config.txt for persistence, then directories and much much more to be excited for!