FYI - I’m using a ZTE Z915 with the regular GL-iNet Chaos Calmer firmware and get full LTE speeds (>50mbps USB=>LAN!) and its been very robust. Other firmwares (notably Padavan on RT-N56U) will not recognize this modem after a power outage and it requires physically plugging and un-plugging the USB cable but it works fine with CC. I’m not familiar with ROOTer firmware but if it has a common base with CC then the ZTE Z915 will probably work too.

-Craig