The GreenPois0n untethered jailbreak for iOS 4.2.1 was released a few minutes ago and I already took it for a spin on my older iPhone 3G sporting iOS 4.2.1.

This step by step guide will show you how to use GreenPois0n to jailbreak your iPhone iOS 4.2.1. It’s worth noting that this version will not hacktivate your iPhone and that so far, there is only a Mac version…

Note: Steps to jailbreak the Verizon iPhone are exactly the same.

Step 1: Make sure your iPhone is on iOS 4.2.1 as GreenPois0n will not work with any other firmware.

Step 2: Download GreenPois0n from our iPhone downloads section.

Step 3: Plug your iPhone to your computer via the USB cable then launch GreenPois0n. Click on the “Jailbreak” button.

Step 4: As soon as you hit jailbreak, you will have to follow instructions for putting your iPhone into DFU mode:

  • Press and hold the sleep button for 3 seconds
  • Continue holding the sleep button while pressing the home button for 10 seconds
  • Release the sleep button while still holding the home button for 10 seconds

Step 5: Your device will now be ready for the jailbreak. Just wait a little bit while GreenPois0n works its magic.

Step 6: Once the jailbreak has been injected in your iPhone, you will see a new icon on your springboard for Loader. Launch Loader and install Cydia from there. Finally, reboot your iPhone and you should have Cydia installed

Step 7: Done!

Enjoy your newly untethered iPhone jailbreak for iOS 4.2.1.

  • iphoneaid

    I believe I didnot follow it right….please try again. If you messed up you can always go back to itunes and restore it to factory default………..even though if you see you won’t able to power up your iphone. Just connect it with itunes

  • comeback kid

    i did all the steps, but still my itouch 4th gen stays on white screen and greenpoison says ( jailbreak failed ) quit ( restart to retry. help please

    • uthenoob

      Learn to jailbreak

  • iphone3gsios4.2.1

    Will this still unlock my iphone 3gs?

  • Ghost

    yes will unlock 3gs

  • ricky

    will this unlock my iphone 3g????? plz hellp i have been trying to jailbrake it for days its 4.2.1 8g

  • cachiusabm13

    whatever, 100 times restore already, gruuuuuuuuu

  • PsYcho

    Greenpoison doesn’t work on iphone 3g on 4.2.1 NOT SUPPORTED read the readme that comes in the GP zip file! The message TRY AGAIN will be displayed after phone is in DFU mode.QUIT TELLING US IT DOES!

  • Tim Rowledge

    So it doesn’t work with the 3G – unfortunately that is *exactly* what the article claims it does. Thus you ought not be too surprised if people attempt to use it for a 3g and then complain.

    • Tiowhatever

      That’s what it said it was for but it didn’t work on my old 3G either. I was able to jailbreak it with redsn0w. So anyone trying to jailbreak their 3G use Redsn0w or if you need to preserve your baseband use Sn0wbreeze with custom firmware.

  • Nash

    I dont think you can unlock your phone after using greenpoison.

  • me

    This article is fake. Greenopois0n does not work with iphone 3g.

  • Thehelp

    You can jailbreake tour iPhone/IPod touch/iPad 1&2 in this site WITH YOUR IPHONE IPOD OR IPAD then tap on the ‘free’ button then tap on the ‘install’ button then wait and DONE tour Idevice is jailbreaken

    I m not English so sorry if this text is ont very English

  • r4z0r

    For anyone having problems try running greenpois0n from the root of your C: drive – it wouldn’t work for me if it was located anywhere else on my machine (iPod Touch 2g)

  • ahsan

    i have jailbroken my ipod touch 2g 4.2.1..then clicked loader..then clicked install cydia,after 50% a message came -“low memory plz delete some files”..then i connected 2 itunes and removed some video.then again clicked loader-install cydia..but it says cydia already installed..then i see cydia icon and click it but after clicking it take few sec and lock my ipod..

  • So I have a 4.2.1 2gen and every time I try to jail break it, it says I have to pay and all of my friends say u can do it for free???!…

    • Rosa


  • r4z0r

    I also had the same error message “low memory plz” – looks like greenpois0n works best on newer models. I just used redsn0w in the end and it worked perfectly

  • THX GUYS IT WORKED!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  • SunT

    Hello, my friend lost his verizon iPhone a month ago and reported missing, he recently found it and gave it to me since he already has one, will green poison be able to jailbreak it, Verizon told me the number is bad so I could give it back to then but that seems pointless, I would appreciate any insight thanks

  • Erin

    Had to try twice as first time failed but follow the instructions to the letter and it definitely works! Thanks very much!

  • grenpoison is the best

  • Anonymous

    I keep getting a “try again” message. The GreenPois0n software won’t run. I have a 3G iPhone, version 4.2.1. Any guidance?

  • Anonymous

    It worked great but I still can’t get a different network carrier to work. Have I missed a step?

  • hey, i want to jailbreak my iphone so i can unlocked it, but i need to restore it first because it was previously jailbreak. But the problem is that i keep trying to restore it from itunes and when it´s almost done, checking the firmware, gives me error 1015 and doesn´t want to restore it.
    does anyone knows what to do?

  • Anonymous

    i tried greenpoison jailbreak, my iphone is in recovery mode…its unlocked Verizon iphone 4.
    plss can anyone help me? how to restore my iphone from recovery mode without restore from itunes

  • Anonymous

    i tried greenpoison jailbreak, my iphone is in recovery mode…its unlocked Verizon iphone 4.
    plss can anyone help me? how to restore my iphone from recovery mode without restore from itunes

  • Maricar Valenzuela

    i tried to jailbreak my iphone 3g ios 4.2.1 using greenpoison rc6.1 for windows and when i tried to put it in DFU mode it said that apple is in DFU mode and my iphone was turned off and greenpoison said try again, and now i can’t open my iphone.. help pls T_T

    • Srinivas J R

      PROBLEM: When your iPhone, iPod, iPad goes into a black screen and
      doesn’t respond just hold down BOTH(sleep and home) buttons for around 10 – 15 seconds. I
      had the same problem…

  • Paul B.

    I keep getting Try Again, this dosn’t work! I have an iPod Touch 2nd Gen 4.2.1 and it wont work help!

  • My Iphone is from London but I live in the Philippines if I jailbreak it would the carrier(i.e Globe communications, Smart & Etc) in the Philippines work? I worry a lot thats why im having second thoughts if i should jailbreak it or not. Please Help

  • Btw, Its my first time jailbreaking PLEASE PLEASE HELP

  • Hi there internet iPhone helpers! I have an iphone 3g not 3gs and a PC running windows. I want to use the baseboard thing but i cant do it with windows. I read the tutorial about jailbreaking with the baseboard but its only for PC. Please help!!!!!!

  • Greenpois0n let me jailbreak my 3g ipod but not my 3g iphone help!!!!!

  • So will any of these work as i have a i-phone 3g on 4.2.1 and a modem Firmware 05.15.04 but it’s the 4.2.1 part that needs jailbreaking,so how do i go about this can someone point me in the right direction as i understand jailbreaking as my i-phone is un-locked anyways. I desperatly need HELP as i cannot load any Apps at all proper messed up because the Firmware box appears saying you need a different Firmware like i know the i-pad 2 firmware can do the job but how do i do all this ???

  • Moooo

    D: its not working it keeps saying failed. I’ve tried MANY TIMES and i keep having to recovering it and trying again D:< I'm losing my patience. its 2g iPod touch 4.2.1

  • paolo

    hi! I’ve just jailbroken my ipod touch 2g (4.2.1) with greenpois0n, but after i’ve downloaded cydia, it crashes everytime i launch it… what can i do? thanks!

  • jacob

    I have an ipod 2nd gen and when i try to do the jailbreak it wont go past getting into DFU when i did all the steps

  • Pablo

    I have an iphone 3G and I want to jailbreak it for more speed, but the link to this tool is broken and I cannot find any tool anywhere