You might wonder what is semi untethered jailbreak, and you may don't have any idea about the meaning of tethered or untethered but don't worry, we will discuss and explain all these expressions and specially the semi untethered jailbreak. Now a days there is a big challenge between iPhone Dev-Team and Chronic Dev-Team to jailbreak iPhone 4, iPhone 3GS, iPod touch 3G and iPod touch 4G running iOS 5 with Untethered jailbreak but not yet. The BigBoss succeded to solve half of this problem with his semi tethered jailbreak let's check it after the jump.

What is the meaning tethered jailbreak :

Tethered jailbreaks are frustrating because they require a computer connection to boot a jailbroken iOS device. The concept of a tethered jailbreak has been around a long time, but essentially it means this: every time your iPhone or iPod touch reboots or the battery dies, you have to connect (tether) your iOS device back to your computer so that the hardware can boot with the aid of the jailbreak application.
What is the meaning of untethered jailbreak :

An untethered jailbreak is the preferred jailbreak because it requires no connection to your computer except for the initial jailbreaking process. You can reboot your iPhone or iPod touch as much as you want without having to tether it to your computer to boot. If the battery dies on a device that has an untethered jailbreak, it’s no big deal you just charge it again and it will boot as usual.

What is the meaning Semi-Tethered jailbreak :

The main issue of tethered jailbreak is that you need to connect your device to computer to use Redsn0w "Just Boot" tethered option every time your reboot your device. Semi-tethered jailbreak come specially to fix this issue, as it allows you reboot your device without connecting it with computer. So now you have untethered jailbreak on iOS 5. But the main issue is that 99% of jailbreak apps and tweaks won't work at all. So what now ? Semi-tethered jailbreak is only a protection for you if your device reboots while you were away from your computer, but you will be able to use the most important functions of you iPhone until you get home and connect it with Redsn0w.

Semi-tethered jailbreak iOS 5 Supported Devices ( Not available on iPhone 4S and iPad 2 ) :

iPhone 4
iPhone 3GS
iPhone 3GS New Bootrom
iPad 1
iPod Touch 4G
iPod Touch 3G

During Semi Tethered jailbreak - Working Functions :

Can use phone, sms (text messages)
Can use every other stock app on iPhone.
Can use other appstore web browsers such as atomic web browser

During using Semi Tethered jailbreak - Not-Working Functions :

Cannot use mobile safari
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”.