Asus AP2400R-E1 - Manual (Page 91)

ASUS AP2400R-E1 2U barebone server 5-17
OS/2 Onboard Memory > 64M [Disabled]
When using OS/2 operating systems with installed DRAM of greater than
64MB, you need to set this option to [Enabled]. Otherwise, leave to the
default setting [Disabled]. Configuration options: [Disabled] [Enabled]
USB Legacy Support [Auto]
This motherboard supports Universal Serial Bus (USB) devices. The
default of [Auto] allows the system to detect a USB device at startup. If
detected, the USB controller legacy mode is enabled. If not detected, the
USB controller legacy mode is disabled.
When you set this field to [Disabled], the USB controller legacy mode is
disabled whether or not you are using a USB device. Configuration
options: [Disabled] [Enabled] [Auto]