Recommended way to clear FPLMN list

[teba99]

Hi,

what is the recommended way on the nRF91x1 to clear the Forbidden PLMN list?

Devices may get denied on networks repeatedly, filling up the FPLMN list. To ensure the devices can still connect when the networks are accessible again I believe we need to ensure the FPLMN list is cleared occasionally.

Our understanding is the official way to clear the FPLMN is using AT+CRSM=214,28539,0,0,12,"FFFFFFFFFFFFFFFFFFFFFFFF"

My question is: Are these ways also possible clear the FPLMN?

• sys_reboot(SYST_REBOOT_COLD)
• conn_mgr_all_if_disconnect(true) followed by conn_mgr_all_if_connect(true)

Thanks,
-- Terrence

[SwRa]

Hi Terrence,

As you already know, the recommended and official way to clear the Forbidden PLMN (FPLMN) list on the nRF91x1 is to use the AT command: AT+CRSM=214,28539,0,0,12,"FFFFFFFFFFFFFFFFFFFFFFFF"  
This command updates the FPLMN file on the SIM, effectively clearing the list. 

Regarding using the followng function,

sys_reboot(SYST_REBOOT_COLD)

The FPLMN list is stored on the SIM, and a reboot does not modify SIM contents.

conn_mgr_all_if_disconnect(true) followed by conn_mgr_all_if_connect(true)

I am not sure if disconnecting and reconnecting all interfaces using the Connection Manager APIs will clear the FPLMN list. I will check this ad get back to you.

Regards,

Swathy

[teba99]

Hi Swathy, thanks for the answer. If the FPLMN is stored on the SIM then I suspect conn_mgr_all_if_disconnect(true) also won't clear it. But if you can find that out, that would be helpful.

[SwRa]

Hi Terrence,

teba99 said:

If the FPLMN is stored on the SIM then I suspect conn_mgr_all_if_disconnect(true) also won't clear it.

That is correct.. using conn_mgr API will not clear the FPLMN list as well. 

Regards,

Swathy

[teba99]

Ok, thanks for confirming!