If you’re like most iPhone users, you probably have more than one carrier account and phone. That’s great, because it means you can switch between carriers and phones without having to re-enter your passcode or unlock your device. But if you’ve ever switched to a new carrier and had to reset your iPhone’s lock screen password, you know that not all carriers support the same methods for unlocking an iPhone. Here’s how to check which carrier your iPhone is locked to:

  1. Open the Settings app on your iPhone.
  2. Tap on “General.”
  3. Under “Device Management,” tap on “Restore.”
  4. If your device is currently connected to a carrier other than the one for which it was originally purchased, Apple will prompt you to enter that carrier’s SIM card information before restoring your device. If your device is not connected to any other carriers, Apple will restore it without requiring SIM card information.
  5. After restoring your device, open the Settings app again and tap on “Phone.”
  6. Under “Cellular,” tap on the name of the cellular service provider with which your iPhone was originally registered (in this example, AT&T).
  7. If the lock screen password for that account is set up correctly, it will be displayed next to “Password” in the “Phone” section of the Settings app; if not, enter that password and re-try restoring from Step 4 above. ..