alzhao
6
There is two S/N actually, another one is dd if=/dev/mtd0 bs=1 skip=$((0x1fc30)) count=16 2>/dev/null
These info is stored in the uboot partition so even if you change firmware, they will remain. Even the MAC address, if not changed by intention, they should remain the same. If you have your own firmware, you can control the process.
If the flash content is totally erased, nothing will be left.
There is no unique ID of the device that cannot be changed!!