If you are looking for a firmware link simply to improve speed or stability, consider these safer alternatives before risking a flash:
for USB tethering on specific router versions (e.g., GL.iNet firmware 4.4.6), which were sometimes resolved by downgrading the router's firmware rather than the modem's. zte mf79u firmware link better
There is a specific site often cited for ZTE updates. If you are looking for a firmware link
Many users have turned their MF79U into an expensive plastic LED light. Here’s what can go wrong: GL.iNet firmware 4.4.6)