yes I did have the same thought and did try carbon as well. I tried various videos, short lengths/small files to large/long duration vids, mostly .mp4 and some .mov, they do play but usually on first reboot and not after. I doubt it’s related to video file issues.
For me, it’s definitely not intermittent. It’s more like plays video at least once on reboot, sometimes second reboot (once I got it to show video 3 times in a row) and then nothing after.
So in my case, video splashscreens works for at least the first reboot after choosing custom. Sometimes it works once or twice after, then stops completely. I can’t say it’s stopped *permanently* as I gave up trying after the 7th or 8th reboot with no video showing.