HI! I have tl-mr6400 v5 flashed with last openWRT (OpenWrt 21.02.0-rc2) and I can't start LTE modem. It's a question to OWRT developers: why defaultly used function of router does not work, and how to set up this modem?
Does this help?
you can try my compiled... stable 21.02.0... need reboot after flashing...
let me know if it working...
You are my hero bro, all works ! thank you