Been using roadtop module for close to three years and recently the screen started to flicker when booting up or whenever in lexus interface, sometimes it would totally blackout, even in reverse gear. However, when in carplay mode, the flicker stops, but when exit to lexus screen, can see the screen flickering. To solve this, unplug the LVDS cable that connects to the box and spray the contacts WD-40 contact cleaner and plug it back firmly, it worked for me.

 

You can also try Deox-it electronics contact cleaner and it also leaves a chemical layer to keep them from oxidizing. It sounds like there was oxidation that was slowly building up over time.