Requirements for USB Boot
5/10/2007
- BIOS Support
BIOS must support INT 13h. During the boot process, Windows XP Embedded assumes that support for communicating with the boot device is present in INT 13h when Windows loads. This is because the NT Loader uses calls to INT 13h to access the disk. INT 13h support must comply with the BIOS Enhanced Disk Drive Services - 2 specification and the USB Mass Storage Specification for Bootability. The newer specification is considered the authority if the two specifications contradict each other. For more information on BIOS requirements for USB Boot, see this Microsoft Web site. - USB Media Formatting and Partitioning
To store the bootable image, the USB media must be formatted properly and contain at least one partition with a Master Boot Record sector (that is, a bootable partition). For more information on formatting the USB media, see Step 1: Format USB Media. - USB Media Performance
Booting and running First Boot Agent on USB media is typically slower compared to a hard drive. To get better performance, use USB media with the following specifications:- Certified hi-speed USB 2.0. USB 1.1 performance is unsatisfactory and not supported.
- NAND SLC flash
- Minimum write speed of 9 MB/sec
- USB Mass Storage and Flash Devices Supported
USB Boot supports booting only from USB Mass Storage and flash media. USB Boot does not support booting from an El Torito CD in a USB drive.