How the Dual SPI Chips (BMC firmware) works

BMC supports dual SPI ROM chips (one for primary bootup and one as a failover backup), which are implemented with identical firmware image. Note that these chips are not soldered but socketed thus can be replaced.

Upon system startup, BMC loads the firmware from its Primary SPI for bootup.

If and when the Primary SPI firmware is not detected after a set time, BMC Watchdog is triggered, instructing the BMC to load the backup firmware from the second SPI for bootup instead.