Cellular via ModemManager not working

I am trying to set up cellular network connection via ModemManager (https://www.balena.io/docs/reference/OS/network/2.x/#cellular-modem-setup) but am running into problem after problem. I have been banging at this for almost a week now with absolutely no progress.

So first, I have tested the modem, sim, and hardware on my linux machine and it works - I am connected to the internet.

After adding a ‘cellular’ file to the system-connections directory, I am seeing the modem. It even has a signal strength of 31, the highest possible. See attached file:

However when I disconnect from Ethernet and reboot the device, it does not connect and it is unavailable via the dashboard.

I am using the NimbeLink Gemalto modem and a Verizon SIM.

Any help would be greatly appreciated. I know this is an issue that many people are facing with BalenaOS.

Hi ,
could you give us a little more information on what type of device and what OS version you are trying to run this on ?

Turns out the Gemalto Modem does not play well with ModemManager. When it recognizes the modem is there, it tries to talk with it - just not the way that the modem wants to be talked too.

The solution was to disable ModemManager completely. And manually talk with the modem.

Thanks Thomas!