問題
Q1
My Hi-Fi B85Z5's USB 3.0 port will not be able to recognize the USB keyboard after system boot to OS, it will need to unplug the USB keyboard again to recognize it. How can I resolve it?

Please try to find the XHCI function in BIOS>Chipset>SouthBridge>USB Configuration>XHCI mode, then set it to [Auto]. After next reboot, system should be able to recognize the USB keyboard properly.