Just got an Udoo Quad, loaded Android 6.01, confirmed it can boot to my 4k TV, but I am now trying to use the 5" HDMI 800x480 LCD here: https://www.amazon.com/gp/product/B075LJX8LS/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 I see 'UDOO' and logo splash screen, but right after that the display is just garbage output. Is there something I need to configure to get it to output at 800x480?
You have to recompile android kernel with your new settings: https://www.udoo.org/forum/threads/android-6-r1-resolution-changing.5104/#post-24663
