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Appendix E: Dual Boot Block
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Appendix E
Dual Boot Block
E.1 Introduction
This motherboard supports the Dual Boot Block feature, which is the last-ditch mechanism to
recover the BIOS boot block. This section provides an introduction to the feature.
BIOS Boot Block
A BIOS boot block is the minimum BIOS loader required to enable necessary hardware
components for the BIOS crisis recovery flash that will update the main BIOS block. An on-
call BIOS boot-block corruption may occur due to a software tool issue (see image below) or
an unexpected power outage during BIOS updates.
BIOS Boot Block Corruption Occurrence
When a BIOS boot block is corrupted due to an unexpected power outage or a software tool
malfunctioning during BIOS updates, you can still reboot the system by closing pins 2 and 3
using a cap on jumper JBR1. When JBR1 is set to pins 2 and 3, the system will boot from a
backup boot block pre-loaded in the BIOS by the manufacturer.
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AMI Firmware Update Utility vX.XX.XX
Copyright (C)XXXX American Megatrends Inc. All Rights Reserved.
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Reading flash . . . . . . . . . . . . . . . . . . . . . . done
-- ME Data Size checking . ok
-- FFS checksums . . . . . . . . ok
Erasing Boot Block . . . . . . . . . . . done
__Updating Boot Block . . . . . . . . 0x00A91000 (13%)