OpenWRT: Routing ke usb tethering
On the Smartphone
Enable USB Tethering on your Smartphone and connect it with the USB cable to your routers USB port. On the router
Use the new usb0 (or for some cases eth1) network device as WAN connection and set the protocol to DHCP client mode.
uci del network.wan uci set network.wan=interface uci set network.wan.ifname=usb0 uci set network.wan.proto=dhcp uci commit network
After commiting the changes to the network configuration bring up the WAN interface to obtain an IP, gateway and DNS address from your Smartphones DHCP server.
Testing the connection
Login to the OpenWrt router with SSH at 192.168.1.1. With logread
ifconfig $(uci get network.wan.ifname)
ping -c 4 www.google.com