PocketBeagle + GamePup LCD not working


I’ve been trying to get my GamePup LCD screen working, but not having much luck. I am running 4.19.94-ti-r42 and have tried using the official bb-overlays’ BBORG_GAMEPUP-00A2.dtbo and jdonk’s BBORG_GAMEPUP-00A4.dtbo, but so far the only sign of life I see is that the backlight turns on.

I have an fbtft device at /dev/fb0 but nothing ever shows on the LCD. Any suggestions?