Asrock P67 extreme4 USB boot problems

Hello,

Upon boot, the PC will occasionally fail to make it past the UEFI splash screen. It will not give any beeps, but will give a debug "b4" code. According to the product manual, this has to do with "USB hotplug."

This problem occurs most frequently when I have my MP3 storage device connected (The Sansa Clip). When the USB device is disconnected, the PC will continue to boot normally.

This also occurs with just the mouse and keyboard connected, although much less frequently. After having issues using the mouse (MS sidewinder x3) in UEFI and legacy modes, I think there may be a problem with that as well.

The only solution I have found is to disable legacy USB or to set it as "UEFI setup only." This makes the "b4" code not appear at all and it POST's perfectly every time.

I have had absolutely zero issues within my OS; the system has been running perfectly otherwise. I have tried other BIOS versions available on the website, but all have the same issue.

Is there a problem with my board or is this simply a UEFI bug that can be fixed with an update?

Thanks,
Adam