OpenWRT on WR1043ND-v1 & Huawei E5577-321 HiLink USB connection

I got Huawei E5577-321 from my internet provider. This MIFI connected via USB works as a network card.

 I couldn't find any reliable instruction that would work. Here is what I did:

Flash OpenWrt Chaos Calmer 15.05.1 on my TP-Link WR1043ND v1.
Enter following in command line:

    # uci del network.wan
    # uci set network.wan=interface
    # uci set network.wan.proto=dhcp
    # uci set network.wan.ifname=eth1
    # uci commit network
    # reboot

Your /etc/config/network file should have following entry:

    config 'interface' 'wan'
        option 'proto' 'dhcp'
        option 'ifname' 'eth1'