Apple has recently released the iOS 4 for all the users. All users can directly download iOS 4 to update the firmware on iPhone and iPod touch. If you have an iPhone and rely on unlock then you can use ultrasn0w 0.93 to unlock iPhone Basebands 04.26.08, 05.11.07, 05.12.01 and 5.13.04. Before using ultrasn0w you need to jailbreak your iPhone. The iPhone Dev-Team has released redsn0w 0.9.5 b5-4 which helps you in Jailbreaking 4.0 Firmware. iPhone Dev-Team has confirmed that redsn0w 0.9.5 works with only iPhone 3G at present. If you have already upgraded to iOS 4 you can download Redsn0w 0.9.5 to Jailbreak iPhone 3G on iOS 4.

How to Jailbreak iPhone 3G on iOS 4 Firmware With Redsn0w 0.9.5

• Download the latest version of iTunes and update your iPhone 3G to the latest iOS 4 Firmware.
• Download redsn0w 0.9.5 for Windows or Mac and also download iOS 4.0 ipsw file for iPhone 3G(iPhone1,2_4.0_8A293_Restore).
• Now run redsn0w 0.9.5 and browse to the original iPhone OS 4.0 ipsw file.
• Now select “Install Cydia” and click Next. You can also check the new features like “Enable Multitasking”, Enable homescreen wallpaer” and “Enable battery percentage”.
• Now redsn0w will show you some instructions to enter into Recovery mode.
  • Hold down the “Power” button and immediately without releasing the power button, also hold down the “Home” button. Without releasing the “Home” button, release the “Power” button and keep holding the “Home” button for 30 second or until the installation starts.
• Your iPhone 3G will reboot once it is jailbroken

Once your iPhone 3G is Jailbroken on iOS 4, you can install ultrasn0w to unlock iPhone 3G.