Steve,
> Right, that's as expected. The only non-free bit about those images is
> that they include some non-free firmware packages too. Otherwise
> they're just the same as the normal free images. Is there a problem
> with that?
Yes, a minor one. Especially for Buster, I expect "apt update; apt upgrade"
to install available upgrades for all packages, including firmware.
Thank you!
Dan