Jailbreak and Unlock iPhone4 on iOS 4.2.1

I Jailbroke my iPhone 4 yesterday smoothly with charm, without any set back :). I went through many blogs and posts before doing this. Now i've done it, hope this post will help other newbies to Jailbreak theirs.

Firstly, get all the necessary files sorted out in one folder.It includes:

• iOS file: iPhone3,1_4.2.1_8C148_Restore.ipsw
• Latest Tiny Umbrella tinyumbrella-4.21.07
• Greenpois0n final for MAC or Windows ( For Windows: greenpois0n )
• RedSn0w for MAC or Windows (For Windows: redsn0w_win_0.9.6rc8 

Once you have all of the above files sorted fasten your seat belt and get ready to Jailbreak :D

If you need the iPhone to be unlocked to use(because you don't have/use official SIM carrier), make sure you have base band 01.59.00. (Settings->General->About->ModernFirmware). This is a must. You cannot unlock you iPhone with ultrasn0w for now if you have updated baseband other than 01.59.00. Have patience and wait for a while , while the dev team releases the new version of ultrasn0w.

Now, once you got it figured out, lets update to iOS 4.2.1 preserving your current baseband 01.59.00.For this:

1. Backup your iPhone so that you don't loose your old data
2. Run Tinyumbrella and close down the iTunes.
3. Save the SHSH blobs for future downgrade if something goes wrong.
4. Start the TSS Server
5. Connect your iPhone.
6. Double check that the TSS Server is running well.
7. You can also check you hosts file(\\system32\\dreivers\\etc\\hosts) to see whether: gs.apple.com is directed to Saurik server or not.
8. Once it is all fine, open iTunes and click (Shift+restore for Windows) and browse the .ipsw file.
9. Wait for some minutes until the iTunes finishes restoring. After that you will be prompted with 1013 error.Click OK and then exit iTunes.( You will see a Connect to iTunes picture in the iPhone screen)

At this point, you have successfully upgraded your firmware preserving your older baseband. Now you need to jailbreak your iPhone.

1. Now you need to enter the DFU Mode for this:
• Press both the Power and Home button until the screen goes black.
• The moment screen goes black, wait for about 2 seconds(approx.) and then release the power button, but keep pressing the home button.
• You will see a black screen if everything goes well. This means you entered the DFU mode. Or else you will go back to "Connect to iTunes Picture".
• This is a little tricky so you might need to give it a try for more than few times(as for my case)
2. Once you've entered the DFU mode, run Greenpois0n,and then hit "Jailbreak".
3. It will take a while.You will see a cmd shell screen in the iphone screen , saying "greenpois0n intialized".
4. After the jailbreak is done, your iPhone restarts with a greenpois0n icon at startup. You will end up with "Emergency Call" screen in different language. :)

That's it. You have successfully Jailbroken you iPhone4. Now you need to activate the iPhone.For this:

1. Switch off your iPhone and run redsnow.
2. Follow the steps, and then check " Install Cydia" only. And nothing more.
3. Click next and hit the Jailbreak now.
4. redsn0w will go through jailbreak steps but it will not alter your greenpois0n jailbreak but just adds Cydia on your iPhone and Hacktivate/Activate your iphone.
5. Once it is complete,your iPhone restarts and  you will be able see the Springboard in your iPhone with Cydia installed.(You can remove the Loader app that was installed by greenpois0n. Just open loader and click "Remove Loader")

Congrats! You have completely jailbroken and activated your iPhone. Now to unlock your iPhone with ultrasn0w.

1. Go to Cydia->Manage->Sources
2. Press Edit-> and then add-> "repo666.ultrasnow.com" and click Add Source.
3. Cydia will download the package. Once it is completed go to the package and Install "ultrasn0w"

That's it, when it is completed, your iPhone will start searching for network regardless of  any kind of SIM. Enjoy the limitless boundaries of your iPhone.

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I hope this will help people who doesn't live in the States or Europe or any other official iPhone seller nation but want to use it. Like my country Nepal. It's useless to pay 2-3 K for some other person to Jailbreak and unlock your iPhone when the "Chronic Dev"/ "iPhone Dev" releases it for free to the community. If you want to pay, let the donation go to them the real brain rather than other third person who monetize it.

Cheers!