ip address del dev br0 scope link fe80::(address)/64
I do not suggest you do this though
Yes, I was thinking about doing that as well, however I'm not sure about what might break in DD-WRT, for instance dnsmasq assumes the interface IPv6, will that keep the old IP or use the new one? There are a couple of other services that might pick on the OS assigned IP and never update it.
On a generic linux system, systemd or network manager allow to change the way the local link addr is generated and/or set something static when the interface is brought up. Is there similar, sanctioned way of doing this in DD-WRT? _________________ 1x Netgear R7800 (latest); 3x Netgear R7000 (latest); 2x Asus RT-N16 (v3.0-r47656); 2x Fonera 2100 (v3.0-r45454).