[NRF9151] Modem does not connect after SIM deactivate/reactivate

[Mlgr]

Hi,

I’m using the Thingy:91X board with the nRF9151 chip, modem firmware version 2.0.2, and SDK version 2.9.0.

We’re encountering a serious issue: the modem does not reconnect after the SIM has been deactivated and then reactivated.

I’ve tried:

• sys_reboot(SYS_REBOOT_COLD)

• Placing the modem offline (lte_lc_offline())

• Shutting down the modem library (nrf_modem_lib_shutdown())

• Forcing a hard reboot via the watchdog

None of these approaches has worked.

Do you have any suggestions for resolving this issue?

The only workaround so far (which isn’t acceptable) is to manually power the device off and on.

Regards,
Mathieu

[Achim Kraus]

Not sure, how you really tested that.

There may be two pitfalls:

- the reactivation of the SIM may take some time (in some cases more minutes, even longer, especially, if you deactivate and reactivate multiple times in just a few minutes)

- some rejection cause are treated "sticky" by the modem. That requires usually to wait some time or do a "lte_lc_power_off/lte_lc_normal" cycle (but I didn't retest that for a nRF9151)

So, let me propose, that you try to wait a minute or so after reactivate the SIM until you test to connect the modem again. If that results in rejected registrations, then try a "lte_lc_power_off/lte_lc_normal" cycle.