The iPhone Dev Team has released redsn0w 0.9.6rc7 with one-click tethered iOS 4.2.1 boot support, so the following guides will help users to do that by using command-line arguments, to bypass the screens normally display while working with redsn0w to Just boot tethered for now.

Boot Tethered Jailbroken iPhone/iPod Touch Running iOS 4.2.1 for Windows

Step 1

Download redsn0w 0.9.6rc7 and iOS 4.2.1 firmware on desktop and place them in a folder

Step 2

Click on Start button and search for cmd and launch it

Step 3

In command prompt, type the following command, but you have to change IPSW file name according to your downloaded one

%homepath%\Desktop\redsn0w_win_0.9.6rc7b\redsn0w.exe -j -i %homepath%\Desktop\iPhone1,2_4.2.1_8C148_Restore.ipsw

For iPhone 3GS and iPod Touch 2G (with old bootroom) enter the following command

%homepath%\Desktop\redsn0w_win_0.9.6rc7b\redsn0w.exe -j -o -i %homepath%\Desktop\iPhone1,2_4.2.1_8C148_Restore.ipsw

Step 4

Now, redsn0w will start working so follow the on screen instructions to enter into DFU mode to boot your iDevice in a tethered jailbroken state

Step 5

All is done.

Boot Tethered Jailbroken iPhone/iPod Touch Running iOS 4.2.1 for Mac

Step 1

Download redsn0w 0.9.6rc7 and iOS 4.2.1 firmware on your desktop and place them in a folder

Step 2

Navigate to Applications > Utilities and launch Terminal and type the following command there, but you have to change IPSW file name according to your downloaded one

open ~/Desktop/folder/redsn0w_mac_0.9.6rc7/redsn0w.app –args -j -i ~/Desktop/folder/iPhone3,1_4.2.1_8C148_Restore.ipsw

For iPhone 3GS and iPod Touch 2G (with old bootroom) enter the following command

open /Users/Desktop/folder/redsn0w_mac_0.9.6rc7/redsn0w.app –args -j -o -i ~/Desktop/folder/iPhone1,2_4.2.1_8C148_Restore.ipsw

Step 3

Redsn0w will start working so follow the on screen instructions to enter into DFU mode to boot your iDevice in a tethered jailbroken state

Step 4

All is Done!