Just performed a sysupgrade from OpenWRT 15.05.1 to LEDE on my Linksys WRT1900ACSv2 using the image found here.
After the upgrade, I found that my interfaces had changed. In OpenWRT, eth0 was configured for my wan interface, and worked as expected using the WAN adapter on the router. In LEDE interfaces configured on eth0 were working only when using the LAN ports on the back of the router. I couldn't get any interface to work on the WAN port, specifying eth1 for my logical wan interface didn't work. (I thought maybe they'd switched).
I've included my /etc/config/network file below. This config works as expected in OpenWRT, but only if I plug my modem into a LAN port on LEDE. Has anyone else encountered something similar, or suggest why this occurred after the upgrade?
config interface 'loopback'
option ifname 'lo'
option proto 'static'
option ipaddr '127.0.0.1'
option netmask '255.0.0.0'
config globals 'globals'
option ula_prefix 'fd52:d193:29db::/48'
config interface 'lan'
option ifname 'eth1'
option force_link '1'
option type 'bridge'
option proto 'static'
option ipaddr '192.168.1.1'
option netmask '255.255.255.0'
option ip6assign '60'
config interface 'wan'
option ifname 'eth0'
option proto 'dhcp'
option peerdns '0'
option dns '54.252.183.4 54.252.183.5'
config interface 'wan6'
option ifname 'eth0'
option proto 'dhcpv6'
config interface 'guest'
option _orig_ifname 'wlan1-1'
option _orig_bridge 'false'
option proto 'static'
option ipaddr '10.0.0.1'
option netmask '255.255.255.0'