How to Jailbreak Your iPhone 4 Using Greenpois0n (Windows) [4.2.1]

Gregoris · Jul 1, 2011

Remember: Do not update to iOS 4.2.1 if you need the unlock. Ultrasn0w does not support that baseband yet. The only exception is the iPhone 4. You can update to iOS 4.2.1 without upgrading your baseband by following this tutorial. iClarified - iPhone - How to Update Your iPhone 4 Without Upgrading the Baseband (Windows) 4.3.1

Step One
Open your web browser of choice and navigate to Greenpois0n.com. Click the Windows link at the bottom of the screen.

Step Two
When prompted save the download to your desktop

Step Three
Double click the downloaded gp_win_rc5_b2.zip file then drag the greenpois0n.exe file to the desktop. Double greenpois0n.exe from the desktop to launch the application

Step Four
Power off your iPhone then click the large Prepare to Jailbreak (DFU) button

Step Five
You will now be instructed on how to place your iPhone into DFU mode. You can get help with this here. iClarified - iPhone - How to Put an iPhone Into DFU Mode

You will be asked to press and hold the sleep button for 2 seconds.

Continue holding sleep; press and hold home for 10 seconds.

Release sleep button; continue holding home for 15 seconds.

Step Six
Once your iPhone is successfully in DFU mode you may click the Jailbreak button.

Step Seven
Greenpois0n will now jailbreak your device

Step Eight
Click the Quit button once the software application has completed.

You'll notice some verbose mode text scrolling on your device.

Step Nine
After the iPhone restarts you'll notice a new Loader application on your Springboard. Press to launch it.

Step Ten
Press to select Cydia then press the large Install Cydia button that appears.

Step Eleven
Once Cydia has installed successfully you can remove Loader by pressing the Options button then the large red Remove Loader.app button.

Step Twelve
Restart your iPhone then run Cydia. Let it do all the necessary updates.

***A big thanks goes everyone who made this jailbreak possible.

tomskater · Sep 9, 2011

Okay Question, After i install the GreenPoisin firmwear it says complete and everything. Phone goes to restore itself....See the spinning skull ect. Then after that just the Iturnes Cd/Plud picture pops up...What am i doing wrong i did every step carfully.

Gregoris · Sep 11, 2011

you seem to be doing it right, just ignore whats going on the screen and concentrate on what greenpois0n is telling you to do

janboyz · Sep 20, 2011

Help Pls

I followed all instructions till step 8;
- press quit
- disconnected the iphone
- attempted to power off iphone but it was stayed stuck with the skull screen for a very long while.
- pressed both HOME & SLEEP and teh apple logo came on and it rebooted.

But after rebooting, its exactly back where I was before the JB, no cydia, no loader.

Did I miss something??

PLSSSSSSSS help.

Another thing, Am on 4.2.1 and if I press RESTORE, it prompts that it will be updated to 4.3.5 !!!!!! Is that true???

Gregoris · Sep 20, 2011

If you are on 4.2.1 then dont restore just skip to the part where you download and use greepois0n

janboyz · Sep 20, 2011

Unleashed said:
If you are on 4.2.1 then dont restore just skip to the part where you download and use greepois0n

I followed all instructions till step 8;
- pressed QUIT
- disconnected the iphone
- attempted to power off iphone but it was stayed stuck with the skull screen for a very long while.
- pressed both HOME & SLEEP and the apple logo came on and it rebooted.

But after rebooting, its exactly back where I was before the JB, no cydia, no loader.

I did this twice and still back at first base.

Where did I go wrong??

janboyz · Sep 21, 2011

janboyz said:
Unleashed said:

If you are on 4.2.1 then dont restore just skip to the part where you download and use greepois0n

Click to expand...

I followed all instructions till step 8;
- pressed QUIT
- disconnected the iphone
- attempted to power off iphone but it was stayed stuck with the skull screen for a very long while.
- pressed both HOME & SLEEP and the apple logo came on and it rebooted.

But after rebooting, its exactly back where I was before the JB, no cydia, no loader.

I did this twice and still back at first base.

Where did I go wrong??

Never mind

Redid it with RUN as Admin and with HOME button pressed till completed and its done!

Thks for all the help

argenthor · Oct 13, 2011

mine's stuck on the scrolling text phase...

Gregoris · Oct 13, 2011

argenthor said:
mine's stuck on the scrolling text phase...

and you are on the 4.2.1 firmware? sorry I have to ask, you would not believe the amount of people that jailbreak with tools that dont support the firmware they are on