Hello @BDSKPEF,
When it comes to the video modes, the support will depend on the version of kernel being used.
For BSP 7, you can set some video modes by adding the tdxargs variable in u-boot:
setenv tdxargs 'video=VGA-1:1280x800'
This will be passed to the kernel as an argument.
VGA-1 can be replaced with the interface you are currently using.
The interface will show up under /sys/class/drm.
Best Regards,
Bruno