The group of iPhone hacker and developer iPhone Dev Team recently released a latest version of the Redsn0w 0.9.10b1, which allows iPhone 4 GSM, iPhone 4 CDMA and iPhone 3GS users to perform an untethered jailbreak.

Here are some of the reminders that you must remember before continuing in jailbreaking your handset:

  • This guide is for handsets iPhone 4 and iPhone 3GS.
  • This guide is for GSM users.
  • Use this guide when you have not upgraded to iOS 5.0.1 yet.
  • Redsn0w 0.9.10b1 supports an untethered jailbreak.
  • Jailbreaking your phone will void the warranty of your handset. Thus, proceed at your own risk.
  • Backup your phone before doing the procedure to ensure that your files will not be lost.
  • Please ensure that you are running on the latest iTunes.

Here is the step-by-step procedure on how to untethered jailbreak your iPhone 4 and iPhone 3GS running on iOS 5.0.1 mobile operating system without updating the baseband using Redsn0w.

Step 1: Download Redsn0w 0.9.10b1 for Windows from this link and Redsn0w 0.9.10b1 for Mac from this link and save the application in a folder named "Redsn0w" on your desktop.

Step 2: You need to download the iOS 5.0.1 firmware file (use Firefox or Chrome to download the firmware file instead of using Internet Explorer or Safari):

Step 3: Double click the Redsn0w zip file and extract the application to the Redsn0w folder.

Step 4: Connect your iPhone to the computer, which should automatically launch iTunes.

Step 5: Navigate back to the Redsn0w folder and launch the Redsn0w application.

Step 6: Click on the "Extras" button.

Step 7: Here click on the "Custom IPSW" button from the options.

Step 8: Navigate to the Redsn0w folder on the desktop and select the downloaded iOS 5.0.1 firmware file (iPhone 4 users - please select iPhone3,1_5.0.1_9A405_Restore.ipsw and iPhone 3GS users - please select iPhone2,1_5.0.1_9A405_Restore.ipsw).

Step 9: Redsn0w should now creating the custom iOS 5 firmware file.

Step 10: Once the custom iOS 5 firmware file is successfully created, you will be notified with a dialogue box. Click on the Ok button to continue. You will notice that Redsn0w has created the custom iOS 5.0.1 firmware file with a prefix "NO_BB_". So custom iOS 5 firmware file for iPhone 4 will be NO_BB_iPhone3,1_5.0.1_9A405_Restore.ipsw and for iPhone 3GS it will be NO_BB_iPhone2,1_5.0.1_9A405_Restore.ipsw.

Step 11: You will now need to put your iPhone into the DFU mode. Redsn0w will take you through the necessary steps:

(a) Hold the Power button on iPhone down for 3 seconds:

(b) Now simultaneously hold the iPhone and keep the two buttons pressed for 10 seconds:

(c) Now release the Power button while keeping the Home button pressed until Redsn0w detects the device:

Step 12: Redsn0w will run the Limera1n exploit.

Step 13: You will be notified when your iPhone is in Pwned DFU mode. The Pwned DFU will allow you to restore your iPhone using the custom iOS 5 firmware file.

Step 14: Now launch iTunes.

Step 15: From the 'Devices' section on the left pane of iTunes, select your iPhone. Now, hold down the Option button (or Shift button for Windows) and click the 'Restore' button.

Important Note: It is very important that you hold down the Option button (or Shift button for Windows) else you will end up accidentally upgrading your iPhone to iOS 5, so please follow the instructions carefully.

Step 16: Navigate to the Redsn0w folder on the desktop and select the downloaded iOS 5 firmware file (iPhone 4 users - please select NO_BB_iPhone3,1_5.0.1_9A405_Restore.ipsw and iPhone 3GS users - please select NO_BB_iPhone2,1_5.0.1_9A405_Restore.ipsw). Click on the 'Choose' button to let iTunes update your iPhone with the jailbroken custom iOS 5 firmware. You will be asked to setup your iPhone either from a previous backup or setup as a new iPhone, select the backup you want for your device (ideally should be the most recent one). Wait for iTunes to finish.