Thanks KY69! the "problem" was extlinux.conf changed to 3072 and working. This is a distribution of only a specific partition (ext4) for h6 and I was not sure if extlinux.conf file had to be modified.
This image have the "sun50i-h6-tanix-tx6.dtb" file as default and seems that all is ok but have not tested sound and hdmi quality, because I use it as a headless sever.
I don't knmow if this is de best .dtb image for Q+ box, but seems fine