[Guide] How to unlock your iPhone 4, iPhone 3GS on iOS5 using Ultrasn0w

Dev-Team has released Ultrasn0w 1.2.4 to unlock the iPhone 4 and iPhone 3GS running iOS 5.0. The following guide tells you how to get this done.

NOTE - Your device will need to have one of the compatible basebands in order to unlock using ultrasn0w.

To check your baseband go to

• Settings > General > About
• Scroll down to iPhone Baseband version under Modem Firmware

The following basebands are supported

• iPhone 4 - 1.59.00
• iPhone 3GS - 04.26.08, 05.11.07, 05.12.01, 05.13.04, 06.15.00 (iPad baseband)

STEP 01 - Preserve your iPhone 4 baseband and update to iOS 5

1. Run Redsn0w
• Select Extras and Select Custom IPSW button
• Browse and select the iOS 4 IPSW file you downloaded before
• Redsn0w will create a custom IPSW file without updating the baseband
• Once done it will show you the name and location of the custom IPSW file. 
2. Enter Pwnd DFU mode
• Select Extras and Select Pwned DFU button
• Follow the on screen instruction to but your device in DFU mode
• Open iTunes and it will tell you that your phone is in recovery mode
3. Install custom Firmware
• Hold Shift (Windows) or Alt (Mac) and Select Restore in iTunes
• Browse and select the custom firmware redsn0w created.

STEP 02 - Jailbreak iOS 5

• You can read our guide to jailbreak your iPhone 4 on iOS 5 using Redsn0w here.

STEP 03 - Unlock iOS 5 with Ultrasn0w

• Open Cydia
• Select manage
• Under Sources Select Edit and then Add
• Add repo666.ultrasn0w.com in the pop-up window which opens
• Now Search for Ultrasnow and install version 1.2.4
• Once installation is complete reboot your device.