How to Manually Clear the FPLMN on a SIM?

What is the FPLMN?

The FPLMN (Forbidden Public Land Mobile Network) is a list stored on the SIM card that contains networks the SIM is not allowed to register on.

A common issue with roaming SIMs occurs when a device attempts to attach to a network that is not permitted by the roaming policy. When this happens:

• The network rejects the registration attempt.

• Depending on the modem or device logic, the rejected network may be written to the FPLMN on the SIM.

• Once written, the device will no longer attempt to register on that network, even if coverage or roaming policies later change.

This can result in the device appearing “stuck” and never retrying a valid network.

When does this happen?

This behavior typically occurs when:

• A device powers on in an unsupported country or network

• A roaming policy temporarily blocks a carrier

• A device is forced to register on a non-supported operator

• Network selection logic repeatedly retries a forbidden carrier

In many cases, rebooting the device will clear the FPLMN automatically. However, some devices may remain in a state where they will not retry the forbidden network without manual intervention.

How to Check if a Network Is Written to the FPLMN

You can confirm whether the FPLMN is present on the SIM by querying the SIM using AT commands.

Refer to the following documentation for modem-specific commands: https://docs.monogoto.io/university/at-commands

(The exact command varies by modem vendor.)

Methods to Clear the FPLMN

There are several ways to clear the FPLMN from a SIM. Choose the method that best fits your setup.

Option 1: Force Network Registration via AT Command

One of the most reliable methods is to force the modem to attempt registration on the forbidden carrier again.

Example AT command:

• AT+COPS=1,2,"310410"

• 310410 is the MCC/MNC of the carrier being forced

• In this example, 310410 corresponds to AT&T

• Replace this value with the MCC/MNC of the carrier that was written to the FPLMN

You can find supported MCC/MNC values in our coverage documentation.

If the registration attempt succeeds or is reprocessed, the FPLMN entry is typically cleared.

Option 2: Insert the SIM Into a Mobile Phone and Manually Select the Network

If you have access to an unlocked smartphone, this is often the easiest method.

iPhone

1. Go to Settings

2. Select Cellular

1. Select Network Selection

1. Turn off Automatic

1. Manually select the carrier that was written to the FPLMN

Android

1. Go to Settings

2. Select Connections

1. Select Mobile networks

1. Select Network operators

1. Turn off Select automatically

1. Manually choose the carrier that was previously forbidden

Once the phone attempts to register on the network, the FPLMN entry is usually cleared.