Asus Crosshair V Formula/ThunderBolt - Manual (Page 104)

3-20 Chapter 3: BIOS setup
3.5.4 USB Configuration
The items in this menu allow you to change the USB-related features.
The USB Devices item shows the auto-detected values. If no USB device is
detected, the item shows None.
Legacy.USB.Support.[Enabled]
[Disabled] The USB devices can be used only for the BIOS setup program.
[Enabled] Enables the support for USB devices on legacy operating systems
(OS).
[Auto] Allows the system to detect the presence of USB devices at
startup. If detected, the USB controller legacy mode is enabled. If
no USB device is detected, the legacy USB support is disabled.
Legacy.USB3.0.Support.[Enabled]
[Enabled] Enables the support for USB 3.0 devices on legacy operating
systems (OS).
[Disabled] Disables the function.
EHCI.Hand-off.[Disabled]
[Disabled] Disables the function.
[Enabled] Enables the support for operating systems without an EHCI
hand-off feature.