Run git checkout 025ffc in the submodule directory and then git add SubmoduleName; git commit -m 'Some message' in the main directory.
(Remember that checking out a commit through its hash leaves you in “detached HEAD state”, meaning that you’re not on any branch. So if there already is a branch pointing to 025ffc in the submodule repository, you should check out that branch; otherwise, you’ll probably want to create a branch there and check it out.)