You have a repository on github, with a submodule that points to another of your repos on github.
You pull both, and push them both to your internal/offline github/gitea.
There's an issue when updating the one that requires a submodule: The submodule still has its path pointing to something on github.
- Go to
.gitmodules
and change the url to your internal github/gitea repository for the submodule. - Run
git submodule sync
in the repo with the submodule - Then you can run
git submodule update --remote
as per normal.