How to override the WAN MAC address
My ISP’s fiber optic modem refused to let any device connect unless it had a specific MAC address. When I got a TP-Link Archer C7 AC1750 router and installed OpenWRT on it, this proved a problem. The MAC address I set through the web interface did not actually override the router’s WAN MAC address. I found a bug describing this issue in OpenWRT’s tracker. Rather than edit
/etc/config/network like one of the comments suggested, I wrote an rc script that set the MAC address.
#! /bin/sh /etc/rc.common
ifconfig "$MAC_IF" down
ifconfig "$MAC_IF" hw ether "$MAC_ADDRESS"
ifconfig "$MAC_IF" up