I have a problem when I try to do a git svn rebase on my repository. It displays :
Checksum mismatch: code/app/meta_appli/app_info.py expected: d9cefed5d1a63
Just happened to me, I run out of space in the middle of a "git svn dcommit" and after that I was getting the same message, "Checksum mismatch".
I just edited .git/refs/remotes/git-svn and replaced the id of the problematic commit with the previous one. Next rebase fixes the problem.