Credit goes to Rickinfl for this solution.
What I have here is based upon what Rickinfl has typed up, but I've changed things up just a bit and added a few steps. I kept getting locked out when changing settings on the LAN IP, but finally got it figured out. This works for 2.2.6.
I'm posting because I thought it may be helpful for those trying to bridge the LAN and WIFI so they're on the same subnet. Hope this helps.
Bridging Wifi to LAN Interface
1- Set up wizard - set the initial LAN IP address to be higher than the final LAN IP, and set the netmask to /30.
For example, if you want the LAN IP to be 192.168.1.1, set the IP for the LAN to be 192.168.1.50 /30 during this step.
2- Interfaces > Assign > Add (it will be auto-named Opt1)
3- Click on Opt1 to set up Wifi Settings
3.1 Rename to Wifi
3.2 Enable interface
3.3 Under “Network-Specific Wireless Configuration” Set mode to “Access Point”
3.4 Set channel to Operate on
3.5 Select WIFI name and passphrase
3.6 Check “Allow intra-BSS Communication”
3.7 Check “Enable WME”
4- Interfaces > Assign > Bridges > Create a Bridge [+ Add] > Selected LAN and Wifi as the interfaces on this bridge > Save
5- Interfaces > Add new Interface [+ Add] > Opt2 > Set Network port = Bridge > Save
6- From Interfaces, click on Opt2 to change options
6.1 Enable Interface
6.2 Rename to “Bridge”
6.3 IPv4 Configuration Type = Static IPv4 >
6.4 IPv4 address = acutual desired IP address of LAN [must set netmask to 30 for now - will change to 24 later] (example above would be 192.168.1.1)
6.5 Save
7- Services > DHCP Server > Turn on DHCP for Bridge > Enabled > Set Range (range with a /30 netmask will be small)
8- Disable DHCP on LAN and WiFi (if they are enabled)
9- Firewall > Rules > Added New Rule > Interface > LAN > Source = Protocol = ANY > Bridge Net > Reset to ANY.
10- Firewall > Rules > Added New Rule > Interface > WiFi > Source = Bridge Net > Protocol = ANY > Rest set to ANY.
11- Firewall > Rules > Added New Rule > Interface > Bridge > Source = Bridge Net > Protocol = ANY > Rest set to ANY.
12- From “Interfaces” set the IPv4 Configuration Type for both LAN and Wifi to None.
13- Router is now reachable by the Bridge IP address (192.168.1.1) and the LAN and WIFI are bridged.
14- Log into router by Bridge IP and change the netmask to /24
15- Change DHCP scope options