booting from sd should work even with proper mtd in place. Get usb uart adapter and provide boot logs.

@Nick A Thank you very much. Newbies will try. 😅

Hello! Are there any plans for a stable minimal/IOT release for the Rock 4D, and if so, what’s the timetable? Thanks!

Stop providing false information, I disproved your theory earlier, please stop. On Armbian, the way to do it via ssh IS TO LOGIN AS ROOT on first run, SSH has logging in as root ENABLED BY DEFAULT on Armbian. This works, and is the way I have ALWAYS done it on Armbian, for years. Here is a link to documentation: https://docs.armbian.com/User-Guide_Getting-Started/#first-login I quote: "The first boot will log you in automatically if you have connected a display via HDMI or if you are connected to the serial console. For SSH, you need to login as root and use the password 1234." If OP refuses to listen to recommendation and keep using putty, OP will have to take this up with the devs of putty, there is nobody here that can/will help with that.

Sorry for filling this thread with my issues. I'm calling it quits on this one and I'll just put up with it. It seems the v4l2request/drmprime stuff is a slow moving beast with ffmpeg/mpv and I have no interest in dealing with the dependency rabbit hole building my own versions. I found some references on the mpv github mentioning possible frame size issues so that's probably what causing my problems. I don't expect it will be fixed until ffmpeg upstream is sorted out. Going by current progress rates that's probably 2 years away.... I did find using --hwdec=drm-copy will play the files without producing the driver error but the green issue is still there. Using drm-copy with 1080p videos would be a little choppy though. I did a grep search on the mpv and mesa driver source code and couldn't find any reference to the "rejecting image due to unsupported offset" error so that must be coming from an external library. I did have a small win as installing the backported Mesa driver did fix some slight screen tearing issues I was encountering on 1080p content.