How can I do to fix my cellular updated failed?

Check for a Carrier Settings update

To manually check for and install a carrier settings update:

1. Make sure that your device is connected to a Wi-Fi or cellular network.
2. Tap Settings > General > About. If an update is available, you'll see an option to update your carrier settings.
3. To see the version of carrier settings on your device, tap Settings > General > About and look next to Carrier.

If you insert a new SIM card into your iPhone or iPad, you need to download the carrier settings for your new carrier.

Take out the SIM card

After removing the SIM card, put it back in. You might need to contact your carrier:

• If the SIM card is damaged, or doesn't fit in the SIM tray, ask your carrier for a new SIM card.
• If you transferred your SIM card from another device, ask your carrier if your SIM card works with your iPhone or iPad.