Jailbreak iPhone 4, 3GS iOS 4.2.1 with Greenpois0n thumbnail

Jailbreak iPhone 4, 3GS iOS 4.2.1 with Greenpois0n

Greenpois0n can jailbreak iPhone 4, iPhone 3GS running iOS 4.2.1 and it is an utethered jailbreak. Chronic Dev Team’s Greenpois0n jailbreak tool brings full untethered iOS 4.2.1 jailbreak for iPhone 4, iPhone 3GS, iPad and iPod Touch as well. If your device is running iOS 4.2.1 firmware, you can jailbreak it using Greenpois0n RC6.1. Unlike RedSn0w, Greenpois0n untethered jailbreak does NOT require SHSH blobs for iOS 4.2b3.

Clean iOS 4.2.1 restore is recommended (UltraSn0w unlocker must NOT do this).
The following instructions will help you jailbreak iOS 4.2.1 on iPhone 4, 3GS using GreenPois0n. It is an untethered jailbreak.

iPod Touch and iPad users should navigate to their respective guides here:

How to: Jailbreak iPod Touch 4G, 3G, 2G iOS 4.2.1 with Greenpois0n
How to: Jailbreak iPad iOS 4.2.1 with Greenpois0n

In this guide, you’ll learn how to jailbreak iPhone 4, 3GS running iOS 4.2.1 using Greenpois0n jailbreak…

How to Jailbreak iPhone 4, 3GS iOS 4.2.1 with GreenPois0n

Your iPhone 4 or iPhone 3GS MUST be running iOS 4.2.1 firmware.

  1. Download Greenpois0n [Windows | Mac OS X]
    Download iOS 4.2.1 (in case you need to restore)
  2. Backup your personal data using iTunes;
  3. Extract the Greenpois0n .zip file and run Greenpois0n;
  4. Click on the Jailbreak button;
  5. You’ll be instructed to put your iPhone4/iPhone 3G into DFU mode:
    1. Press and hold the sleep button for 2 seconds;
    2. Continue holding sleep; press and hold home for 10 seconds;
    3. Release sleep button; continue holding home for 15 seconds.


  6. Greenpois0n will begin jailbreak iPhone4/3GS on iOS 4.2.1 as soon as it enters DFU mode;
  7. Once the jailbreak process is complete, a Complete button will appear on greenpois0n and there’ll be a flood of commands on your iPhone screen;
  8. Just wait for your device to reboot automatically. Your iPhone 4/3GS has been jailbroken. One last thing to do here is to open Loader app from your iPhone home screen and install Cydia.

That’s it! You’ve sccessfully jailbroken iPhone 4, 3Gs iOS 4.2.1 with Greenpois0n jailbreak.

Also checkout:
How to: Jailbreak iOS 7
How to: jailbreak iOS 6.1.2, 6.1.3, 6.1.4
How to: Jailbreak iOS 6.1
How to: Jailbreak iOS 5.1.1
How to: Jailbreak iOS 4.2.1

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14 comments… add one
Pontus May 6, 2013, 11:50 am

I have this problem, instead of the ”Get ready to start” to the Release sleep button; continue holding home it says
”Plug AppleTV in to USB”
”Plug in power adapter”
”Press and Hold MENU and PLAY/PAUSE”
”Release Both Buttons”

ahmed alamri July 20, 2013, 5:27 pm


iphone useer February 13, 2014, 10:53 am

by jailbreaking our phone will it reset all data???

Jailbreak EYE February 18, 2014, 2:46 am

simply backup your iPhone before restoring… and when your device is updated then restore it from backup to get back your old stuff..

Isaac April 19, 2014, 2:19 pm

I can’t switch on my phone after this step.!!

Jailbreak EYE April 19, 2014, 2:23 pm

Hold down the Power and Home button for 10-15 sec then leave the Home button, Apple logo should appear.

ipod 3g user July 6, 2014, 12:00 pm

the link for green pois0n on window doesn`t work please fix it

zander September 9, 2014, 10:54 pm

my iphone 3gs is unactivated, how can i hacktivate it

Omaromarharr December 2, 2014, 8:16 am

Do I need a pc to complete this jailbreak?

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