On Fri, Jun 20, 2014 at 10:00 PM, Scott Duplichan scott@notabs.org wrote:
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.
OH believe me, I have too. That's when I learned a mac of 00:00:00:00:00:00 actually works.
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.
very interesting. Thing is, this is pretty much the antithesis of build-time serial number creation ... which is the thing that I don't see scaling.
thanks!
ron