Chapter 8: Recovering Witness Bios: Dup Flashing - Dell PowerEdge XR4000w Installation And Service Manual

8
Recovering Witness BIOS: DUP flashing
About this task
As the Witness board contains two SPI EEPROM BIOS chips that are mixed by the chassis manager (CM), a corrupt BIOS on
the active chip should be a recoverable situation.
The assumptions here are that:
1. the chassis manager (CM) is functional
2. the Witness MCU is functional
3. the Witness board is detectable by the chassis manager (CM)
Given these, applying a standard Witness BIOS DUP should:
1. Tell the chassis manager (CM) to start flashing the inactive BIOS EEPROM
2. Once BIOS flash is complete chassis manager (CM) toggles the EEPROM mux. This sets the currently active, corrupt BIOS
as "Inactive" and the newly flashed BIOS chip as "Active"
3. The Witness should boot successfully from the now active EEPROM
Recovering Witness BIOS: DUP flashing 57