Edit the “/tmp/system.cfg”

Change the line that contains “dhcpc.status=disabled” to

dhcpc.status=enabled

add the following lines

dhcpc.1.devname=br0         
dhcpc.1.fallback=192.168.1.20
dhcpc.1.fallback_netmask=255.255.255.0
dhcpc.1.status=enabled

Save and exit and save changes

/usr/etc/rc.d/rc.softrestart save

Log into the GUI and verify everything looks correct. Under the network tab it was still showing that it had a static address, although it pulled a DHCP IP.