Hi mkjeong,Thank you for your question. I have a few questions to ask in order to be able to help you:1. Are you using a linux or android filesystem?2. Are you outputting to HDMI or using an LCD display supplied with the board?3. Did you compile the kernel/userspace mali drivers yourself?Typically we see issues like this when using single buffering, and so in the mean time you could check that you are in-fact using double buffering.ThanksChris