As the module meets new networks, the FPLMN list will slowly be updated, removing previous entries and clearing the list. If the phone does not connect to any network with manual selection, the FPLMN list is not the problem it is most likely something at the network operator level. If the phone does not clear the FPLMN list, use manual selection options on the phone to clear individual networks on the list: go to network selection in the settings menu, choose manually select networks, wait for the phone to scan the networks in the area (this can take a couple of minutes), and then pick a network to connect to. Take the SIM out of the device and put it in a phone. This is unfortunately not possible with embedded SIMs. When it turns on, the device will try to connect to previously forbidden networks if it has successfully cleared the SIM. Then turn it off again and put the SIM card in again. If you are using plastic SIMs and the device is within reach, take it out and turn the device on. Some devices will clear the FPLMN list when a new SIM is inserted into them. If you don’t have access to AT commands, there are a couple ways you can use the GSMA standards to attempt to clear the FPLMN list.
What if I don’t have access to AT commands? You can read a full overview of the network selection command here: AT+COPS. Please consult the manufacturer’s AT Command Manual for more information Warning: A few cellular modules will not attempt to manually connect to a forbidden network. This will set the list back to the prefix only, meaning that the FPLMN list is clear. To clear the FPLMN list, you can run the update binary (214) AT+CRSM command with 24 F’s: AT+CRSM=214,28539,0,0,12,"FFFFFFFFFFFFFFFFFFFFFFFF" If you get any response other than 24 Fs (the list’s data prefix) as shown above, then the FPLMN needs to be cleared. The AT+CRSM command tells the SIM to give us the FPLMN datafile (28539) in binary (176). You can first check that it needs clearing by running the standard AT command: AT+CRSM=176,28539,0,0,12 You’ll need access to the device with the SIM in it and be able to run an AT command. You may need to speak to the manufacturer or supplier if you are unfamiliar with AT commands. The following options require knowledge of how to use AT commands on your device.
How do I clear the FPLMN (forbidden network) list? You can also read more on how devices use PLMN lists on the SIM during automatic selection. This is because the device will not attempt to connect to networks in the FPLMN list while the SIM is in automatic network selection mode. If the SIM has since been activated and you are still not seeing a connection, you should try clearing the FPLMN list. If a device is turned on when a SIM is not activated or if a device goes into a country that is not on the network safe list (aka allow list), the device will write all local networks it tries to connect to to the FPLMN list. When a module attempts to connect to a network and is denied, it will write that network to the FPLMN list on the SIM, thus preventing it from attempting to connect to that network again. The FPLMN list is a dynamic list that is maintained by the device’s cellular module. This shortens the time it takes to connect because the device won’t look for networks that aren’t available.