There is a distinct difference between a tethered and an untethered jailbreak for iDevices. With the former, you get stuck at the Apple logo every time that you reboot your iPhone or iPad unless you plug it back into a PC. That’s not the case with an untethered jailbreak. So, what exactly is a “semi-tethered” jailbreak then?
Well, it’s somewhere in between. A tethered jailbreak for iOS 5 has been around for some time, but no one has come up with an untethered jailbreak yet. With the semi-tethered jailbreak from Big Boss (you can get full instructions on TheBigBoss.org), you get some of your core functionality back when you reboot the device, even without having to reconnect back to a PC or Mac.
This isn’t quite as good as truly untethered, but it’s a start. When you run out of juice on the road or need to reboot your iDevice for whatever reason, at least you can still make calls and send and receive text messages. The semitethered jailbreak also allows for other stock apps too. While you can’t use mobile Safari, you can use other web browsers like Atomic.
That’s the good news. The bad news is that this iOS 5 semi-tethered jailbreak still doesn’t work with the iPhone 4S.