My GPU does not have any video output ports as they are mining version and I need to connect via onboard VGA. The matter is that when it'll show "Started hiveos" after that I'll only see a blink "_" and nothing more! what's wrong?
There might be driver conflict to start graphics interface.
During boot, you might see IP address, try to access it with SSH or VNC.
I did unattached all my mining cards and only connected via onboard VGA and after this solution, i saw Hiveos console and it asked me for "RIG ID". Let me test your solution. I'll write my answer here.