Posted inHOWTO

BigBoss Releases Semitethered Jailbreak For iOS5

As you might know, iOS5 currently has a tethered jailbreak. So what’s a semi tethered jailbreak? In short, it is protection for if your device reboots while you’re on the road.

Jump over the break for more details…



What is a tethered jailbreak?

This means that after you have jailbroken and installed most stuff you care about, you go to reboot your device, and it will no longer boot. You will be either stuck at apple logo forever, or you will get to itunes restore screen. When this happens, you have to hook up to your computer and use redsn0w “just boot” feature which gets you rebooted successfully again. It’s not all bad, as iOS5 is pretty stable. But if your device crashes and reboots while you’re out on the road, you are screwed and without a phone until you get home.

What is an untethered jailbreak?

An untethered jailbreak is one that does not have such problems. Here you can reboot and the device reboots successfully. Because we are using the limera1n exploit discovered from Geohot last year, we are always guaranteed a tethered jailbreak on last generation devices. A new exploit will need to be found to untether us.

What is a semi tethered jailbreak?

The semi-tethered jailbreak will allow you to reboot on the road, but with limited functionality. It is enough that you are no longer stranded, and you can use your phone, text, and many other features. This is just until you get home and can use redsn0w again to “just boot tethered”. Once you do that, you’re back to fully functional state.

Here is a summary of what you can and cannot do when in semi-tethered reboot state:

  • Can use phone, sms (text messages)
  • Can use every other stock app on iphone.
  • Cannot use mobile safari
  • Can use other appstore web browsers such as atomic web browser
  • Cannot use mail app. You could install a gmail app from appstore or such instead.
  • You cannot use any jailbreak tweak, app, cydia until you boot tethered.
  • While in the semitether booted state, you should not add a jailbreak ios5 notification such as sbsettings to notifications during this state or your device will be stuck in a respring loop until you get home to “boot tethered”.


  • The device will take longer to boot up. When you reboot, it has to reload every service. It will respring a couple times also.
  • According to Saurik, there are some “problems” to reloading all daemons on the fly. This is why mobile substrate installation requires “reboot device” in cydia. I have not experienced any of these problems, but I am not promising they do not exist. This is why we will need testing to see which problems may occur.

The semi tethered jailbreak was only tested on iPhone4 GSM running iOS5. But the package will be update…

To install the semi tethered jailbreak, add the following repository to cydia: