This guide and tutorial will show you how to unlock your iPhone 4 running iOS 4.0.1 using UltraSnow 1.0-1. This method will not only work with the iPhone 4 but also with older models. UltraSnow 1.0-1 will unlock:

  • The iPhone 3G, iPhone 3GS, and iPhone 4
  • Basebands 01.59.00, 04.26.08, 05.11.07, 05.12.01 and 05.13.04

Note that UltraSn0w will work no matter what your iPhone model number is.

In order for UltraSn0w to work, your iPhone must be activated. If it isn’t, follow these instructions to activate your iPhone without the original SIM card.

Step 1: Jailbreak your iPhone using JailbreakMe.

Step 2: Go to Cydia and search for UltraSn0w. If it’s not there, you might have to add the following repo: repo666.ultrasn0w.com

Step 3: Install UltraSn0w.

Step 4: Reboot your iPhone.

Done! Your iPhone should be unlocked. You can now pop in any SIM card. If you unlocked an iPhone 4, you might have to trim the new SIM so it fits in the tray.

Because the iPhone doesn’t support T-Mobile’s 3G frequencies, T-Mobile users in the US should turn off 3G in Settings > General > Network.