Requirements for USB Boot

• BIOS Support

  To boot from USB devices, platforms must support booting from USB 2.0 with INT 13 natively.

• 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.

• USB Mass Storage Device Must Be Enabled

  USB Mass Storage Device must be enabled for USB boot. If USB Mass Storage Device or its parent devices are disabled, the system will not boot from USB devices, even in safe mode. The following screen capture from Device Manager shows USB Mass Storage Device and its parent devices.

  

  In the system shown, the following devices must be enabled to boot from USB media:

  • USB Mass Storage Device
  • USB Root Hub
  • Standard Enhanced PCI to USB Host Controller

See Also

First Boot Agent

Last updated on Wednesday, October 18, 2006

© 2006 Microsoft Corporation. All rights reserved.