Device serial number

allard · ‎2025-02-24

Simple question:

If i'm right the serial number returned by cat /sys/firmware/devicetree/base/serial-number is the UID from BSEC. Where is the code responsible for setting this value? I've seen the function get_board_serial in u-boot but it doesnt seem to be implement for the stm32mp1 board.

allard · ‎2025-03-21

To answer my own question:

The serial number is injected into the device tree in UBoot using the serial# environment variable, see: https://github.com/STMicroelectronics/u-boot/blob/40469ba48e30e280371a057ce63f7dcb505095b7/common/fdt_support.c#L200

View solution in original post

PatrickF · ‎2025-02-24

Hi @allard ,

not sure it answer your question.

The 96-bits UID is set in factory (i.e. fused inside OTP), readable thru BSEC. It cannot be altered and it is guaranteed to be unique within a STM32MP serie.

Regards.

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allard · ‎2025-02-25

This I understand.

What i'm trying to do is replace the function that reads the UID with a function that reads my own serial number programmed into the OTP.

I've looked for the function that does the reading but i've not found it. I'm using the distribution package. So my question is: where is the read implemented, so I can make a .patch to patch this to read my own serial number.

allard · ‎2025-03-21

To answer my own question:

The serial number is injected into the device tree in UBoot using the serial# environment variable, see: https://github.com/STMicroelectronics/u-boot/blob/40469ba48e30e280371a057ce63f7dcb505095b7/common/fdt_support.c#L200