We’ve seen yesterday that we the release of the updated UtraSn0w unlock, there are a few to be met to unlock iPhone 4.2.1. This unlock will work for the iPhone 3G or iPhone 3GS with baseband 04.26.08, 05.11.07, 05.12.01, or 05.13.04. It will also work with iPhone 4 with baseband 01.59.00.

But what happens if you’re not on one of those basebands? Depending on your phone model and configuration, you might have to update the baseband to 06.15.00, which is fully unlockable, then unlock using UltraSn0w.

In this tutorial, I will show you how to use RedSn0w to update your baseband to 06.15.00 so you can unlock your iPhone 3G/3GS 4.1.2…

Step 1: Before doing anything, make sure to read this. Seriously, read it over and over again. There is very important information in there that you must know before proceeding.

Step 2: Make sure you have the latest version of iTunes installed on your computer. If not, update iTunes.

Step 3: Make sure you have iOS 4.2.1 on your iPhone 3G or 3GS.

Step 4: Download RedSn0w 0.9.6 beta 5 as well as iOS 4.2.1 for your iPhone 3G or 3GS from our downloads section.

Step 5: Launch RedSn0w and browse for the iOS 4.2.1 firmware you downloaded in the previous step.

Step 6: Once the IPSW is identified, click Next. RedSn0w will start preparing the jailbreak data.

Step 7: Now make sure you select to “Install Cydia” and “Install iPad Baseband”. A warning will pop up. Again, make sure you read and understand the risks associated with this.

Step 8: Make sure your iPhone is turned off and plugged in your computer. If it’s not, plug it in, then turn it off. Click next, and be ready to get your iPhone in DFU mode.

Step 9: Hold the Home and Power button together for 10 seconds. Release the Power button while still holding the Home button for a few seconds. Then let RedSn0w run its magic.

Done, your iPhone is successfully running a jailbroken iOS 4.2.1, and we have updated the baseband to 06.15.00.

If your device is an iPhone 3GS with old bootrom, you won’t have any problem after that. If however it is a newer bootrom, you will notice that you iPhone shows the “connect to iTunes” logo every time you reboot it. It’s normal. While very inconvenient, it’s the way it is.

To go around that, launch RedSn0w, plug your iPhone in and select “just boot tethered” just like the image below. It will kick boot your iPhone.

How to Unlock Your 4.2.1 iPhone 3G or 3GS

Now that you’ve gone through these steps, you can easily download UltraSn0w from Cydia to unlock. Simply install it, reboot your iPhone, and you will be unlocked.

  • Evgen
  • Matt

    I have a Iphone 3GS and ive just updated it to 06.15.00 with RedSnow 0.9.6 beta 5 and i am now stuck at the apple logo it keeps loading and freezeing i get a small circle in the middle of the apple logo, sometimes the circle is spinning and sometimes it freezes and im now stuck at that place, i dont know what to do.. my problem is that i dont want my iphone to get stuck every freaking time i have to rebott it and when i do that i have to open redsnows program to just boot teathered its ridicilous what if i want to sell my iphone… come on someone help me with this!!!!!! you have no idea how thankfull i am if you help me :/

    • Andrew

      Matt, I went through this same nonsense! Okay, so hopefully this helps. After spending many hours trying to fix this, I simply plugged the phone into PC and ran redsnow. Following the first couple of steps above, select ur current IPSW for ur current firmware (Should already be downloaded on ur computer)(make sure ur using the iOS for IPHONE and not IPAD!). Now, when u get to the screen where it asks u what u want to do: (Install Cydia, Install custom bundle, install ipad bb etc.) ONLY choose the “Install Cydia” option follow the instructions for df mode and let red snow do its thing. This finally allowed my iphone to boot up YEA! However, I didnt have the any wi fi option under settings after doing this, so I wasnt able to open cydia and download ultra snow. In order to correct my wi fi problem, simply ran through the baseband upgrade again (the above steps) (this time redsnow took longer to flash baseband)! Finally! My wi fi worked and i was able to open cydia and download ultrasnow to unlock, rebooted iphone and popped a Tmobile sim card in and made a phone call!!! Now, I read all night my 3gs NEW bootrom was going to be tethered after the bb upgrade but NOPE! I restarted the device multiple times and it works perfect without connection to a PC, dont know why but who cares! Basically, if it doesnt work the first time try it again! This crap is very temperamental…Good luck man, let me know if it works!

  • sanjay varma

    i purchased iphone 3gs from ebay usa,the seller told it was unlocked by apple care.version4.2.1
    i cant start the phone even once,the screen is just dead.when connected to itune it says iphone in recovery mode.even restore option not activated in itune screen.i tried to but cant get it to dfu mode .apple people say it is locked by at&t and only they can do unlock.please help

    • Snos2

      Hi enter dfu
      Hold power button count to 3
      Then hold home button count to 10
      Then release power button count to 10
      Update via itunes it will fail
      Then jailbreak with green poison then install cydia goto manage
      Sources click pn redsnow install then go back to redsnow and install 1.2
      Hope this helps snos2

  • Leela

    The rebooting is taking a really long time. I followed the steps, but it just won’t reboot. Why is it taking so long? Help, please!

  • a.i

    Step 7 on redsnow is different. Instead my options are: “Install Cydia”, “Install custom bundle”, “Just boot tethered right now”, “Just enter pwned DFU mode right now”. NO “Install iPad Baseband”. What do i do????????? thx

    • poYo

      download redsnow beta 5 <<<<<< happend to me ^^

  • Runaway

    Does anyone know if there is a way to jailbreak iphone 3g 4.2.1 without using a computer?

    • Sciencetor2

      As of ios 4.0.2 jailbreaking without a computer is impossible, as all browser based exploits have been patched. All subsequent jailbreaks are bootrom based and therefore the phone must be in dfu mode for them to work, and will require a computer

  • mannerohardy

    i have iphone 3g with baseband(modem firmware) 05.15.04
    so now im using iPhone1,2_4.1_8B117_Restore jailbreak
    my question is…can i update iphone 3g to 4.2.1 with unlock or without unlocking?
    what if i have a problem updating to 4.2.1 ? can i simply restore with itunes?

    im new …too many comment i read LOL~~~ some success some failed so that why im asking you all guys please help me okey……

  • G from Powell

    When I click on (RedSn0w 0.9.6 beta 5: Windows) in downloads section I get “Page not found”. What is the problem? (RedSn0w 0.9.6 beta 4: Windows) works. Could I use beta 4 instead beta5?

  • mannerohardy

    yes i did it yesterday and now im usingiphone 3g iOS 4.2.1 jailbreak without unlock right now 😉

  • stpwu

    Hi, I can’t find RedSn0w 0.9.6 b5, so I used 0.9.6 b6. Does it matter? I followed all steps. After Step 9, the iPhone 3GS reboots, but Redsn0w stays in “wait for reboot”, Redsn0w doesn’t seem to see the iPhone. I checked the modem version is still 5.15.04, not 6.15.0 and can’t find Cydia. What did I miss?

  • Snos2

    Had the same problem make sure you have correct firmware i used wrong one got same problem wait for reboot ?

  • stpwu

    @Snos2, Thanks for the hint. However, which is the correct firmware? I’ve tried several versions of 3GS firmware from the download page. None of them work. Appreciate any more information.

  • JiN


  • That0neGuy

    I am currently using Greenpois0n as the Jailbreak software and I am wondering can i just download Redsn0w and run that with Greenpois0n already on. Will this still work?

    • That0neGuy

      i solved my issue nevermind.

    • Don’t do that, greenpois0n is an UNTETHERED jailbreak and redsn0w is a TETHERED!!!!! The difference is that with tethered every time you install a Cydia app you need to do the just boot tethered option in redsn0w otherwise it will stay on the apple logo until you do so. With an Untethered jailbreak you don’t need to do this. Hope this helped :P!

  • suraj

    i purchased iphone 3gs from ebay usa,and when isyn. with itune then can,t b sync. and want to restory fac. setting and and then the restory my iphone is locked
    so wht for do..
    pls help me

  • Adam R

    Yet another cry for help…
    i am using a windows PC (I Know, i Know) ….
    My iPhone 3G /4.2.1 iOS and a baseband of 05.15.04
    What is the best program for me to use? I am sooo confused

  • Adam R

    Ok, now my neighbor is convinced i am crazy..just ran out mumbling to myself with this iPhone in my hand totaly frustrated…I forgot mention in the las posat that i use Tmobile
    My iPhone 3G /4.2.1 iOS and a baseband of 05.15.04 carrier Tmobile

  • tunde

    My iPhone 3G /4.2.1 iOS and a baseband of 05.15.04
    it was given to me by my brother and it already has cydia installed. do i just download UltraSn0w to unlock it?

  • tunde

    My iPhone 3G /4.2.1 iOS and a baseband of 05.15.04
    it was given to me by my brother and it already has cydia installed. do i just download UltraSn0w to unlock it?
    i forgot to mention it already has ultrasnow installed! but i,m in nigeria now and even tho i use 1800 gsm the iphone has not recognised my sim in nigeria

    • That0neGuy

      You will have to download redsnow and just add the iPad baseband which will give it 6.15.0 and then download UltraSn0w from Cydia to unlock it. (ultrasn0w doesn’t work with 5.15.04)

  • tunde

    When I click on RedSn0w 0.9.6 beta 5: Windows in downloads section I get “Page not found”.
    What is the problem?
    Please, which one can I use instead?

  • tunde

    Pls it appears RedSn0w 0.9.6 beta 5: Windows in downloads section is not available.
    What is the problem?
    Please, which one can I use instead?

  • drublic

    Hello, I have a quick question if someone knows how to guide me on this one, my push notifications from 3rd party apps like whatsapp, heytell, facebook, twitter… are not working. The ones like Messages and Skype they do work I think cause they are iOS core ones.
    I’ve already tried downloading push fix or push doctor but didn’t work, my youtube works fine so is not related to that.
    When I jailbroke with Sn0wbreeze I selected to hacktivate my iphone so that it could activate with any carrier hoping this could have fix this issue that I’ve been having since iOS 4.1.
    Any ideas anyone? Thanks!

  • Steve01

    Been waiting for ages to reboot but doesn’t seem to be doing anything. Can anyone help? Thanks.

    • Snos2

      Press and hold power and home untill phone reboots this will force file system to rebuild but hold untill phone phone goes off a apple logo comes back on normally around 20 seconds

      • Snos2

        If still fails rerun jb make sure u have correct firmware

      • Steve01

        Hi Snos2,

        That worked. The problem now is that it is just showing the USB & iTunes logo and doesn’t move from there.

        Thanks for the help.

      • Steve01

        Ignore my last comment. After 15 minutes the screen went blank so I assumed it was done. i clicked finish and switched on the phone but it was still the same. No Cydia or anything. Any help would be appreciated as I’m slowly losing my cool 😉

  • Steve01

    Info if required:

    Version: 4.2.1
    Model FW: 05.15.04

    Using Redsnow 96b5 – iOS iPhone2,1_4.2.1_8C148a_Restore

  • abb

    hey .. i have a 3G and i have done the jailbreak but like the first comment it stuck on the apple screen .. i have tryed doing it another 2 times but its still staying on the apple .. can anyone help :s ????

  • RichDawg9er

    Since the article was published in 2010 do we still have to use RedSn0w 0.9.6 beta 5 or the latest release? I’m looking to Unlock an old iPhone 3G with iOS 4.2.1 Baseband 05.15.04 so I can use my old T-Mobile SIM in it. I want to DO IT RIGHT – according to all the tutorial guides here.

    Some places I read to use the latest software release, but most of the tutorials and videos I have found refer to 0.9.6 beta 5 which is old now. So what should I do?

  • Pwnage face

    use pwnage tool…it’s better.

    RedSn0w 0.9.6 beta 5 <— doesn't have the "install ipad baseband" option

    someone mentioned downloading redsnowbeta 5 but i say get a mac and use pwgage tool.

  • mark

    hello i have the iphone 3g 4.2.1 with firmware 05.15.04 and im trying to download the ipad baseband but when it says “please wait patiently” the window suddenly disappears and nothing happens. i waited 30 minutes then decided to unplug the phone. any suggestions? i have windows 7 btw

  • Len

    With the baseband 6.15.00 installed can I upgrade the iPhone software? If I do, what are the jailbreak options? Thanks.

  • Maricar Valenzuela

    i tried to download RedSn0w 0.9.6 beta 5 but the server said page not found – files. please help T_T

  • iphone is stuck in the downloading jailbreak data! any help?