Canon 800d/T7i clean-hdmi? I've just bought a Canon 800d to use that as live cam recorder (using elgato game capture).

The problem is that the hdmi output has the focus box and I've managed to remove that only in manual focus mode, but I'd really like to have auto focus.

Do you know any solution?

I think that magic lantern is not yet compatible with the 800d.
Download Sparkocam and your problem will go away. I am using a T3i and a T6i for the same live steam. Your other option is remove autofocus from the lens and switch it to manual