That's what I meant. I tried with the combo update this time, but the same error comes up when the system restarts and I choose the MacOS Install Data to boot from....
mount -uw /
Try to run the combo update again and when it restart, press the space bar at the Clover Boot selector, enable single user mode and when it finishes to boot to the prompt type the following.
Code:mount -uw /
This will mount your system volume as read-write.
Then type exit and press enter to continue the updater loading process.
Let me know if that helped and post a screenshot like the one you did in your original post.