Thank you, first of all! So you mean that even in vendor's preinstalled Android they don't use GPU for that? I installed there VLC + couple of players from vanilla stores - all of them have no issues with HW decoding at all... According to their status Cedrus could be much easier way - VLC stated there as supported already

You could check the UUID with blkid /dev/mmcblk0p1: UUID="b23e98d0-700e-4a09-88b6-95675ee524f5" Then check if this is the same in /boot/armbianEnv.txt and /etc/fstab

yes, tried different tv/monitor always with the same problem, solved by disabling video driver in u-boot.

I think you can Find things: https://forum.armbian.com/topic/18255-rk3566-and-armbian/ @f3nyx if you have patience you can support this device for community.

We are very sorry that your device was damaged, I suggest you contact the manufacturer of the product so that they can give you all the support you deserve as a paying consumer of the product. If the manufacturer is listed in the link below, I believe you will have better luck with your device. https://www.armbian.com/partners/ I would like you to replace your device with a device from my preferred manufacturer https://www.banana-pi.org/