Waveshare 3.5C screen turns white after poweroff

Hardware
1

Hello,

I build a Zynthian, using a Raspberry Pi 4, Hifiberry, Zynthian Kit v2 and a Waveshare 3.5C display, build into a 3D printer housing. The Zynthian works terrific…

But when I poweroff the Zynthian, the Waveshare screen turns bright white with Max backlight.
Does anyone know a way to turn off the screen and the backlight after powerdown?

Kind regards and keep up the good work…

Remco

2

Once a PI powers off, there’s very little that can be done with it. For instance there is no longer 5Volts on the USB connectors.

3

I was thinking, maybe cutoff the 5V power to the display using an extra GPIO.