> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hologram.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Clear the FPLMN (forbidden networks) list

> Understand when and how to clear the SIM's Forbidden PLMN list using AT commands.

## About the FPLMN list

The FPLMN (Forbidden Public Land Mobile Network) list is stored on the SIM and contains networks the device should avoid.

<Warning>
  **Caution:** Only clear the FPLMN when instructed by Hologram support or your device vendor. Doing this at the wrong time can disrupt registration.
</Warning>

## Check the FPLMN

```bash theme={null}
AT+CRSM=176,28539,0,0,12
```

If the response shows 24 Fs, the list is empty:

```bash theme={null}
+CRSM: 144,0,"FFFFFFFFFFFFFFFFFFFFFFFF"
```

<Frame>
  <img src="https://mintcdn.com/hologram-b29df2a6/gBXuuJ66IPyI_nhw/images/troubleshooting/fplmn-read-empty.png?fit=max&auto=format&n=gBXuuJ66IPyI_nhw&q=85&s=77d44bc4fbc9e7be19883b8c8dba7581" alt="AT+CRSM read showing 24 Fs indicating empty FPLMN" width="1892" height="288" data-path="images/troubleshooting/fplmn-read-empty.png" />
</Frame>

## Clear the FPLMN

Before writing, set minimal functionality if required by your module:

```bash theme={null}
AT+CFUN=0
```

Write exactly 24 Fs:

```bash theme={null}
AT+CRSM=214,28539,0,0,12,"FFFFFFFFFFFFFFFFFFFFFFFF"
```

<Warning>
  **Warning:** Include exactly 24 Fs in the payload.
</Warning>

<Frame>
  <img src="https://mintcdn.com/hologram-b29df2a6/gBXuuJ66IPyI_nhw/images/troubleshooting/fplmn-write-clear.png?fit=max&auto=format&n=gBXuuJ66IPyI_nhw&q=85&s=aa1a7e9aae095f5656b520b61bc2bc7a" alt="AT+CRSM write showing 24 Fs to clear FPLMN" width="2886" height="452" data-path="images/troubleshooting/fplmn-write-clear.png" />
</Frame>

Restore full functionality afterward:

```bash theme={null}
AT+CFUN=1
```