The following guide will help you to know that how to jailbreak iPod Touch 4G, 3G untethered running over iOS 4.2.1 with Greenpois0n RC5.

Warning: Users who rely on Ultrasn0w unlock must update to stock 4.2.1, otherwise stay away from Greenpois0n RC5 tool as they will lose the unlock.

Note: This guide is written for Mac OS X users.

Jailbreak iPod Touch 4G/3G Untethered on iOS 4.2.1 with Greenpois0n RC5

Step 1

Create a folder on your desktop, download Greenpois0n for Mac, and unzip it in your created folder, suppose with the name Untethered Jailbreak

Step 2

Double click on Greenpois0n icon to launch it inside your folder

Step 3

Attach your iPod Touch to Mac, power it OFF, click on Jailbreak button on Greenpois0n screen

Step 4

Greenpois0n will instruct to put your iPod Touch into DFU Mode, so continue with those instructions carefully

Step 5

When your iPod Touch will enter into DFU mode successfully the jailbreak process will automatically start and on completion of process just click Complete! button

Step 6

After restart of your iPod Touch you will find Greenpois0n Loader app sitting on Springboard, so tap on it to launch that

Step 7

Select Cydia there, and tap on Install Cydia button

Step 8

Once Cydia will be installed, it will prompt to remove Loader from your iPod Touch, so tap on Remove button to do that

Step 9

Reboot your iPod Touch by pressing Home button

Enjoy, your iPod Touch 4G/3G over iOS 4.2.1 is successfully jailbroken with Greenpois0n RC5.