ron minnich [mailto:rminnich@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). ] ]ron
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.
Thanks, Scott