I am working on a device with Quectel EG25G modem with multiplexed SIM card slot (poor man's dual sim:)). Such configuration will require often APN changing. I am afraid that it is possible to wear modem's flash memory in case when ModemManager+NetworkManager overwrites APN config on each SIM/Operator switch. My concern's reason is that U have to manually input bearer (MM only), or the APN data is stored inside NM con config instead of index of APN array from modem interior.

So my question is: Does ModemManager+NetworkManager combo rewrites APNs on each connection change or uses already saved inside modem?

1 Answer 1


So I have installed wireshark and examined communication between device and a modem. Unfortunately it sets APN and other GSM data every time. This can be harmful for modems flash memory. Such malfunction killed modems in the history of my company.

So I moved to qmicli. It has option to create profile and connect using only the profile ID. Wireshark study showed, that only the profile ID is sent over the USB, so that's safer and more foolproof, if the modem engineers let APN and other params be overwritten everytime.

qmicli man page: https://www.freedesktop.org/software/libqmi/man/latest/qmicli.1.html

Hope this will be helpful.

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