Hello @eeb,
The best way to achieve that would be trough the CLI. In this case, you could use the same config file from one of the balenaCloud downloaded images and put it in your custom image. There’s more information on how to do that here.
I’m not sure how host OS updates would play out if you go this path though (see this post for more information). I’ve reached out to our OS team to see if there have been any developments.
Cheers,