Cannot add vlan id to ar750

I noticed the switch does not show the wan port in luci-network-switch. which is normally vlan 2 on most routers. and I cannot add a vlan id to assign to the extra lan port (1 or 2) thanks.

What I’m trying to do is assign the first port lan1 to the wan interface so the router acts like a bridge for an addtional wan interface. thanks

There has two physical interface for AR750, eth0 and eth1. In our firmware, eth1 supports vlan, so you only can configure eth1 to vlan, while eth0(wan) cannot be configured to vlan.