I just did a complete dump of mtd0

cat /dev/mtd0 | strings

But I cannot find the serial number nor the DDNS anywhere in the uboot section of the AR-150.

Is the serial number still there or was it removed when enlaring U-Boot for the AR-150?

As said I would like to use the qrcode on the box to link the serial number to a particular box. That can only be done when I can read that serial from the firmware somehow. Thanks for any info.