Why, oh WHY does sysfs.edge(self_pin, NONE) create a permision denied error when the GPIO pin in question doesn't support interupts and /sys/class/gpio/gpioxxx/edge doesn't get created in the first place! (And why doesn't the #OrangePi3lts manual not say that half of the pins don't support interrupts?)

The joys of Pi, but at least got the #EnderS1 stock screen working with Klipper at last....