Help connect the 4G modem to the router - Installing and Using OpenWrt - OpenWrt Forum
Building an LTE Access point with OpenWRT Rooter -
OpenWRT - Install and Configure LTE modem in QMI mode - Quectel EC25 & Wallys DR4029 - YouTube
OpenWRT 4G WWAN configuration
Amazon.com: USB 4G LTE Router,4G/3G Low Power Consumption Mobile Hotspot Long Battery Life Small Portable SIM WiFi Dongle,Support Notebook,Tablet,Laptop(European Version) : Electronics
Amazon.com: 4G LTE USB Modem WiFi Dongle, Mini Portable USB 4G Wireless Network Smart Router for Tablet Laptop Notebook, 2 LED Status, Plug and play(US Standard) : Electronics
Connect 4G USB modem to WRT2200 - Installing and Using OpenWrt - OpenWrt Forum
Setting up a 3G/4G modem with OpenWRT on the MPR-L8 or A5-V11
Setup 4G/LTE Dongle on Raspberry Pi 3 - Network and Wireless Configuration - OpenWrt Forum