I have tried again with trixie, ensuring that the kernel patches were taken... no difference. Then I build a Bookworm Armbian image, with linux 6.15.4. It wasn't visible wether the kernel was downloaded from armbian, or the last one was included in my OS image. Just for fun, I tried it with Bookworm's default ffmpeg-5.1.6, with xfce with compositor off... and I got a 1080p MP4 playing with 5% mpv log: Note that mpv still complains about unsupported hwdec: drm I repeated the test with compositor ON: killall xfwm4 && xfwm4 --compositor=on --display :0.0 & I still got hardware accelerated 1080p. My guess up to this point is that the problem was trying it with Debian Trixie. Then I tried with the ffmpeg-x.x.x-v4l2 request Adding the repo, updating, and checking the update: Then I tried playing the mp4, with compositor ON. I got hardware acceleration: 5% CPU or less... and no complaint about unsupported hwdec: drm In summary: use Armbian Bookworm, linux edge 6.15.4, turning the compositor off is optional. Armbian Trixie (and the correspoinding ffmpeg 7.1.1) will result in "unsupported hwdec: drm"

use my works: h616.tar.xz

follow the official instructions, change these dts to user overlay, simplicifed deployment just use `sudo make install` h616.tar.xz

Currently I am running HA supervised on Debian 12 bookworm. Debian boots from USB drive without any issue. So your suggestion should work I believe. Thanks for the suggestion. You are quick as always to reply.

I would. Happened in the past but no clue which hw. Probably also something aw related.