Apple seeded iOS 6.1 beta 4 to developers which can be jailbroken tethered on A4 devices, will not work on A5 devices.
Devices supported are iPhone 4 (CDMA), iPhone 4 (GSM), iPhone 3GS and iPod Touch 4G.
Jailbreak iOS 6.1 Beta 4
Download RedSn0w 0.9.15b3 for Windows and Mac OS X.
Connect your device to computer and launch Redsn0w which you downloaded from the link mentioned above. Windows users should run Redsn0w as Administrator.
Click on “Extras” button in Redsn0w and then click on “Select IPSW” button and select the iOS 6.0 firmware file.
On the main page of Redsn0w click on “Jailbreak” button and enter into DFU mode. You will have to follow on-screen instructions.
To enter DFU Mode-
* Hold down Power (corner) button for 5 seconds.
* Without releasing the Power button, also hold down the Home (bottom center) button along with the Power button for 10 seconds.
* Without releasing the home button, stop holding down the power button for up to 15 seconds.
Now, RedSn0w will process the iOS 6 firmware.
Tick on the option “Install Cydia” and then click the Next button to begin the actual Jailbreaking process.
The jailbreak process will take some time. Don’t use the computer.
When device is jailbroken it will enter reboot again.
Boot Tethered iOS 6.1 beta 4
Launch RedSn0w >> Extras >> Select IPSW >> Select iOS 6 firmware >> Just Boot button.
Your device is jailbroken on iOS 6.1 beta 4.