- Vulnerability, Exploit: geohot
This is geohot's latest jailbreak utility. It is an updated version of purplera1n but now uses geohot's implementation of the usb_control_msg(0x21, 2) Exploit. It has been released for Windows and Mac. It will jailbreak all devices on 3.1, 3.1.1 and 3.1.2. It will even jailbreak OTB iPhone 3GS and iPod touch 3G.
So far, Blackra1n does not support hacktivation, so if you don't have a legitimately activated iPhone, then you can not activate it with Blackra1n
How about a 3G/3GS unlock?
At this moment in time, geohot's only unlock is purplesn0w, which only supports the 3.0 baseband. (ultrasn0w only supports the 3.0 baseband also.) And once you update (the baseband), there's no going back for most. Furthermore, in order to use Blackra1n, you must be on 3.1 firware already, and the Apple stock IPSW updates the Baseband. So far, the Baseband is locked on this version and a timescale for an unlock is unknown. If you must keep your unlock, you will need to use the Dev-Team's Pwnage Tool to jailbreak, as it will retain the old, unlockable Baseband. Then you will be able to use either Purplesn0w or Ultrasn0w as you see fit as a soft-unlock for you iDevice
How to use
All you have to do is head to the blackra1n website and download the application on to your computer. Then, plug in your iDevice and press "Make it ra1n". Then you wait. As this is a non-ramdisk based tethered Jailbreak, the iDevice may not boot. If is does not boot, just press "make it ra1n" again.
Installing Package Managers
The Blackra1n procedure installs an App on to the device, APTly named "Blackra1n" that handles the package manager installation. With it you can install Cydia, Icy and/or Rock. After installation, the device will respring and the package manager of your desire will be on your SpringBoard. After installing, you may remove the Blackra1n App using the "uninstall" button within it. Don't worry - this does not remove the Jailbreak, just the App to install Package Managers if you no longer need it