Ds Lite Top Screen Flickering and Mirrored Image.

Can confirm it’s the potentiometers. If you’re looking at the motherboard and you see the two potentiometers near the volume dial of the motherboard, the one on the left is the top screen while the one on the right is the bottom screen. I’ve had some units where they only needed a small millimeter of a turn to the right to stop the flickering, and other units where I needed to tweak between each unit for the right power.

In some cases it may be a balance of tweaking both to get one screen or both to stop flickering. Trial and error, but just turn up the Pots by a small degree each time until you reach a satisfactory conclusion.