Apple fans have been waiting for a new Jailbreak and a Carrier Unlock for the new iOS 4.2.1, and the iPhone Dev Team has released the goods. It may not be simple, but at least a solution is available.
Note 1: Jailbreaking and Unlocking your iPhone is your own responsibility and is to be done at your own risk. Please make sure you are using the correct tools and are within correct parameters for this Jailbreak/Unlock, read all instructions completely and check relevant links provided below for further information. If you are still not sure what to do…stay away from it.
Note 2: This iPhone 3GS and iPhone 3G Carrier Unlock is for those who have a baseband later than 05.13.04. ALL older bootroms (which depend on an Unlock carrier) should WAIT.
Note from iPhone Dev Team:
“YOU DO THIS AT YOUR OWN RISK! PLEASE UNDERSTAND THE CONSEQUENCES OF UPDATING TO 06.15.
1. There is no way to come back down from 06.15, and there’s no hiding the baseband version from Apple. You’ll be voiding your warranty in a very obvious way.
2. If some future baseband comes out with a critical fix, you won’t be able to update to it if it remains down in the 05.xx sequence (then again, you wouldn’t update to it if you wanted to keep your unlock anyway).
3. Starting with FW 4.2.1 if you have 06.15 on your iPhone you won’t ever be able to restore to stock firmware (it will fail). You’ll need to only restore to custom IPSWs (then again, if you’re unlocker you should already be doing that).”
Jailbreak and Update to Baseband 06.15.00 with Redsn0w 0.9.6b5 for iPhone 3GS and iPhone 3G
Step 1: Download the newest iOS 4.2.1 for either the iPhone 3GS or iPhone 3G.
Step 2: Update/Restore to the new iOS 4.2.1 firmware using the IPSW file you just downloaded through iTunes 10.1.
Step 3: Download Redsn0w 0.9.6b5 for Windows or for Mac
Step 4: Begin Redsn0w 0.9.6b5 and direct it to iOS 4.2.1 firmware to continue the iPhone Jailbreaking.
Step 5: (Required for Upcoming Carrier Unlock) Go ahead and mark “Install Cydia” and ALSO “Install iPad baseband” selections and then click continue “Next”. This will have Redsn0w replace the baseband in iOS 4.2.1 / 4.1 with the 06.15.00 baseband.
Step 6: Make sure your iPhone 3GS or iPhone 3G is PLUGGED In and turned OFF prior to continuing…”Next”.
Careful: You will receive a screen that will ask you to:
a. Press and HOLD the “power” button (keep holding)…after…
b. While still holding “Power”, also press and hold “Home” button….then…
c. While still Holding both, release “Power” button and keep holding “Home” until installation begins.
Step 7: Redsn0w will do the rest of the work for you. Your iPhone will restart automatically and will be: Jailbroken, running the new iOS 4.2.1 and have the Baseband 06.15.00 updated.
Continue to the Unlocking iOS 4.2.1 for iPhone 3GS and iPhone 3G below.
Jailbreak and Update to Baseband 06.15.00 with PwnageTool 4.1.3 for iPhone 3GS and iPhone 3G
Step 1: Download the following:
a. iPad 3.2.2 Firmware which is needed for the Baseband update (for the Carriier Unlock)
b. iOS 4.2.1 or 4.1 Firmware
c. PwnageTool 4.3.1
i. there is an updated file that needs to be added to the Pwnage Tool. To install it, go to the PwnageTool file you have downloaded, right click it, select “Show Package Contents”, find “Contents/Resources/FirmwareBundles/” and copy/paste: iPhone2,1_4.1_8B117.bundle. (download here)
Step 2: Begin PwnageTool 4.1.3 and direct it to the iOS 4.2.1 or iOS 4.1 firmware
Step 3: You will now be able to update your Baseband to 06.15.00, so you will be able and Unlock it later using Ultrasn0w 1.2.
Step 4: Direct PwnageTool 4.1.3 to the iPad iOS 3.2.2, which will replace the Baseband in iOS 4.2.1 and iOS 4.1 with the 06.15.00.
Step 5: Select the Next arrow. PwnageTool will now create a custom ipsw file.
Step 6: Enter DFU Mode:
a. Hold BOTH Power and Home Buttons for 10 Seconds
b. While continuing to hold the Home button, release the Power Button (Hold Home for 10 more seconds)
c. Your iPhone should now be in DFU mode.
Step 7: Restore iPhone to your custom firmware by:
Start iTunes and click on your device icon from the sidebar.
Press AND hold left “alt” button [“Shift” in Windows] and THEN click “Restore” (NOT – “update” or “check for update”). Release the Alt/Shift button.
Step 8: Be Patient, for now many steps are automatically done, including your iPhone restarting. In the end, you will now have a Jailbroken iPhone with the new iOS 4.2.1/4.1 Firmware and the updated 06.15.00 Baseband.
Continue to Unlock iOS 4.2.1 for iPhone 3GS and iPhone 3G Below.
Unlock iOS 4.2.1 for iPhone 3GS and iPhone 3G with Ultrasn0w 1.2
After you have Jailbroken your iPhone and Updated the Baseband to 06.15.00 using one of the two methods above, you can continue to the Ultrasn0w 1.2 Carrier Unlock.
Step 1: Go to Cydia on your iPhone, Select the “Manage” Tab from the bottom and then “Sources”
Step 2: Touch “Edit“, then “Add“, then enter the url “http://repo666.ultrasn0w.com” and then touch “add source“.
Cydia will run its rounds, update and finish installing the source.
Step 3: Search for “ultrasn0w 1.2” and install it.
Step 4: Restart your iPhone and you will now have a completely Jailbroken and Unlocked iPhone 3GS or iPhone 3G running the newest iOS 4.2.1 (or 4.1).
Instructions, Video and Images Via: RedmondPie please check them out for further details and information.