Why does this download-file exist? And why does a SD-card with that file (for SD-card) not boot?
Running LE11 from the internal emmc requires upstream u-boot; which that image contains. It cannot boot the box from SD card because vendor u-boot doesn't support the extlinux boot files needed for upstream u-boot. so you boot the box image (so emmc is not in-use) and then download and install the board image (that image) to emmc. Others have grasped that and succesfully installed. You haven't, but that's not really something I can solve. Your weird screen issue is not reported anywhere before so it's probably rare or something odd and unique about your environment. And the AMLGX image is not perfect, nor advertised as being perfect. But it works good-enough for me and my very typical media collection, and likely others have a similar experience (active install numbers are increasing). So sorry it's not for you, but we can't please everyone. I suggest you stick with 9.0.2 or bin the device or run Android or whatever you prefer.