Asrock ad2550ru3s3 用户手册

In this section, it will display the available devices on your system for you 
to configure the boot settings and the boot priority.

Select boot option #1.

Select boot option #2.

Set the boot priorities for USB devices. 

This shows the number of seconds to wait for setup activation 
key. 65535(0XFFFF) means indefinite waiting.

If this item is set to [On], it will automatically activate the Numeric 
Lock function after boot-up.

Use this item to enable or disable OEM Logo. The default value 
is [Enabled].
AddOn ROM Display
Use this option to adjust AddOn ROM Display. If you enable the 
option “Full Screen Logo” but you want to see the AddOn ROM 
information when the system boots, please select [Enabled]. Con-
figuration options: [Enabled] and [Disabled]. The default value is 
[Enabled].