Well you told me that MAC address can be changed so I was looking for something else, can ddns be changed even if we flash the router with another firmware or it stays the same no matter what firmware it is? anyway the SN is different from the one written on the back of the router, I got “c5b7b1f2ee470d7f” with “dd if=/dev/mtd0 bs=1 skip=$((0x1fc20)) count=16 2>/dev/null”. It should begin with “6b0f8bxxxxx…”