Is there a way to have OSMC function in 480i resolution over HDMI? The closest I’ve gotten by tinkering with the config and cmdline is the splash screen showing, perfectly fine, then cutting either to black or a seemingly progressive signal, which my CRT doesn’t support.
Not sure. If you post a log via SSH, maybe we can see.
Did you try to put this at the end of your cmdline.txt? video=HDMI-A-1:720x480@60i
Did you monitor support this?
Install edid-decode and take a look
edid-decode /sys/class/drm/card1-HDMI-A-1/edid