I am currently working with a small Raspberry Pi Model A setup (and want to stick at this model until I can grab a model Zero). It was modified to be as quiet (aka black) on boot as possible which works fine.
So far there is a custom created service starting a video with the hello video demo on boot. Even that works fine and the video is playing nicely.
The problem is I want to get rid of the colored rainbow square on boot because it is the last ugly experience. There is the option to set disable_splash to 1.
But this not only results in a not shown splash screen but also in making the video shown flickering (black diagonal stripes moving over the screen).
What are the detailed influences of disable_splash and how can I get rid of the colored square (disabled or tainted black) while keep the video playing nicely?
Here are only the lines of config.txt which are not commented out
hdmi_group=2 hdmi_mode=87 hdmi_cvt=800 480 60 6 0 0 0 display_rotate=1 config_hdmi_boost=0 gpu_mem=96 disable_splash=1