I did. I flashed router with latest firmware snapshot available on web-site. I tried installing OVS on this snapshot and it was NOT available.
So, I decided to build firmware with OVS as development build. It built fine. However, during install, I got kernel mis-match as posted. Initially, I created firmware without "config" changes posted on Github for OVS. It failed. Then I tried with config changes. It failed again with kernel mismatch.