[coreboot] setting smbios values from the OS

Scott Duplichan scott at notabs.org
Sat Jun 21 07:00:04 CEST 2014

ron minnich [mailto:rminnich at gmail.com] wrote:

]realistically, though, it's hard for me to see how setting the
]serial # at firmware image build time scales. And setting it after
]boot makes no real sense either -- it's not really a serial number
]if you're changing it at that point. 

]But some way to customize the binary images with a serial number
]seems most workable, if you're going to put the serial number in
]the firmware image at all (which never made sense to me either
]--serial #s are supposed to be indelible, and firmware images are
]not indelible).

Putting the serial number in the same flash chip as the main
firmware is a cost reduction measure used with desktop and other
low cost boards. I have even seen a board where the MAC address
lives there. The only protection for those items is that the
flash utility given to the end user knows to skip that area.

The way I have seen the serial number programmed is at
manufacturing diagnostics time. The board is PXE booted to a
diagnostic image. The image runs a script that first erases
the entire flash chip. It then programs it with the OEM firmware
image. The OEM image contains a blank serial number. The script
then prompts for operator input. The operator pulls a barcoded
serial number label from a roll and attaches it to the board. The
operator then scans the label with a barcode reader. The script
uses the barcode data to find the serial number in a database.
The script then runs a special flash utility that reprograms only
the serial number portion of the flash chip.

If the end user flashes the firmware by any method other than the
supplied utility, the serial number will be lost. It can still be
read from the barcoded label though. 


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