root has no shell

Hello All, Ive got a big Problem. I changed the root shell to /bin/false. There is neither a user in the sudoers nor is there any other root-user or even a user in the root group. Is it possible to switch back the shell to /bin/bash or sh or something? Ive tried: sudo -- not in sudoers su -s /bin/bash -c "command" -- "using restricted shell: /bin/false" thanks in advance, Ulrich