Etherboot/LinuxBios on Supermicro P4DPE

steven james pyro at
Thu Apr 10 08:42:01 CEST 2003


LinuxBIOS for that board (and many others) supports two copies of
LinuxBIOS, fallback and primary. The fallback image is intended to be old
and stable and it's purpose is to act as a sort of rescue image. The
primary image is the one that gets updated to the latest and greatest, and
is meant to be more versatile and complete.

The fallback image is loaded at the top of the flash, and always recieves
control at power on or reset. It does very minimal setup (switch to 32bit
flat memory protected mode), checks and clears the CMOS boot bit, and if
it was set, jumps to the primary image. This way, if the primary fails,
hitting reset will boot from the fallback image alone.

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