Download Jailbreak iOS 4.2.1 Using Redsn0w 0.9.6rc7 On Mac OS X

Below Download Jailbreak iOS 4.2.1 Using Redsn0w 0.9.6rc7 On Mac OS X. The above command assumes assumes that both redsn0w and the IPSW are on your OS X desktop, so modify it if you want to place them elsewhere. When you double click the command, your Redsn0w 0.9.6rc7 will automatically skip all the steps, including selection of iOS firmware and the ‘Just booth tethered now’ option to directly take you to the screen where you are asked to put your iPhone in DFU Mode.
Extract Redsn0w 0.9.6rc7 zip file contents and place ‘Redsn0w.exe’ and the shell command ‘boot-ipt4g.command’ on your desktop. Also place your iOS IPSW firmware for your iDevice on desktop.
All download links given at bottom. Next double click on ‘boot-ipt4g-command’ to run it. This will automatically run the following command in your Mac OS X terminal:

open ~/Desktop/redsn0w.app —args -j \ ~/Desktop/iPod4,1_4.2.1_8C148_Restore.ipsw

The above command works for iPod Touch 4G on iOS 4.2.1. In order to make it work for your iPhone or iPad, right click on the command, select ‘Open With –> TextEdit’, and edit the command to reflect your current IPSW firmware. Replace ‘iPod4,1_4.2.1_8C418_Restore.ipsw’ to the exact name of your device’s firmware.
 Download Redsn0w 0.9.6rc7 for Mac OS X