I made a shallow clone of a repository with git clone --depth=1. I made some changes... apparently without understanding the complications of shallow clones...
Why can't I push from a shallow clone? seems to have some additional commentary. In fact, look at this comment:
Update 2015: with Git 2.5+, you will even be able to fetch a single commit. See "Pull a specific commit from a remote git repository"
So perhaps you can't push, but from the other side, you can pull. Have you tried that?