How to Fix “No Service” and Cellular Data Not Working After iOS Update

When your iPhone displays “No Service” or “Searching…” after an iOS update, the baseband modem firmware needs carrier provisioning refresh.

Why This Problem Happens

• Outdated carrier profile incompatible with modern iOS release.
• eSIM profile de-synchronized from carrier HLR.

Step-by-Step Troubleshooting Procedure

Step 1: Check for Carrier Settings Update

Objective: Install official carrier network patch.

1. Connect to Wi-Fi, then go to Settings > General > About.
2. If an update is available, a prompt will appear saying “Carrier Settings Update”. Tap Update.

Step 2: Toggle eSIM / SIM Card Line

Objective: Re-initialize cellular modem handshake.

1. Open Settings > Cellular.
2. Tap your SIM/eSIM line, toggle “Turn On This Line” OFF, wait 15 seconds, and toggle it back ON.

Step 3: Verify Modem Firmware in About Settings

Objective: Confirm hardware health.

1. In Settings > General > About, scroll down to “Modem Firmware”.
2. If this field is completely blank, your baseband chip has suffered hardware failure requiring service.

Verified Troubleshooting Tips

• Eject the physical nano-SIM tray with a SIM tool, wipe the gold contact pad with a microfiber cloth, and re-insert.

Frequently Asked Questions

What does “Cellular Issue Detected” mean?

This alert indicates iOS ran diagnostic tests on the cellular modem and found a hardware communication error.