I did that. The OpenVIX time still jumps around. Even after wiping all firmware and then re-installing it. OpenVIX is the only image that does this (so far).
Johnny, how does it "jump around"? Is it a few seconds type jump forward or back, or all over the place? Also, do you do complete power-downs, or just Standby's or ? Also, is your Mio hard-wired ethernet, or are you using it WiFi?
I had that problem with the image OpenVix 5.2.040, and whenever I tried doing a "Restart Enigma" after making some changes. I changed my Time Server to: time.windows.com and the problem went away. My Mio is hard-wired ethernet.