Persistent setting default APN

[caeg]

My custom device uses nRF9151 and we're using SDK 2.6.0 with modem firmware 2.0.1.

When the device connects to the LTE network it derives a default APN, however, my provider recommends that I use a different APN. I'm trying to find a way to make that alternate APN be the default and persist in the device.

Case 334155 indicates several prj.conf items which can be used to pre-configure the APN in the device firmware.

CONFIG_PDN=y
CONFIG_PDN_ESM_STRERROR=y
CONFIG_PDN_DEFAULTS_OVERRIDE=y
CONFIG_PDN_INIT_PRIORITY=89
CONFIG_PDN_DEFAULT_FAM_IPV4V6=y
CONFIG_PDN_DEFAULT_APN="my-apn"

This does work for me, however, it means that a given firmware build is tied to work with a certain cellular provider. We may have a population of devices using a different cellular provider and it would be ideal to use the same firmware for both cases.

Is there a way to persist an APN setting in the modem itself rather than app firmware?

Failing that, I suppose in app firmware we might be able to discover which carrier the SIM is configured for and make modem_lib calls to set APN accordingly.

[emdi]

No, there isn't. You can configure the default APN at build time with the project configuration settings you found, but you can't let those be saved in the modem firmware. You have to save those in the application non-volatile memory, load them on startup, and use the AT commands used in the PDN library to override the defaults before switching to CFUN=1.