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Difference between revisions of "Tethered jailbreak"
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| + | A device with a '''tethered jailbreak''' has to be plugged into a computer while booting up, so that a jailbreaking program (like [[redsn0w]]) can help the device boot up jailbroken. It is called a "tethered" jailbreak because your device has to be ''attached'' to a computer to boot up properly. |
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| − | Tethered means being basically "attached" to your computer in a way; you must boot your device by running code on it (via the dock connector) to make use of an exploit. Devices are tethered because there is one or more area where the device fails one or more signature check along the way due to the jailbreak. The device is able to boot up because there is a way to execute code via USB that allows you to bootstrap to a pwned (no signature check) [[iBSS]], [[iBEC]], or [[iBoot (Bootloader)|iBoot]] to finish the boot process. |
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| − | To boot tethered, you need to use the software which you used to jailbreak and click "boot tethered" |
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| + | == Technical detail == |
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| − | ==[[N72ap|iPod touch 2G]]== |
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| − | The initial jailbreak for the [[N72ap|iPod touch 2G]] was tethered, until the hybrid dev team released the [[0x24000 Segment Overflow]]. The codename for the tethered jailbreak was [[redsn0w Lite]]. |
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| + | When a device is booting, it loads Apple's own [[kernel]] initially, so a jailbroken device must be exploited and have the kernel patched each time it is booted up. |
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| − | ==Linux== |
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| − | Currently, certain devices are capable of booting to Linux. The downside is that this is a tethered boot. |
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| + | An [[untethered jailbreak|'''untethered''' jailbreak]] includes powerful enough exploits that if the user turns the device off and back on, the device will start up completely, and the kernel will be patched without the help of a computer – in other words, it will be jailbroken after each reboot. |
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| − | == Semi-tethered == |
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| − | In some circumstances, a tethered jailbreak can be made "semi-tethered." When a device is "semi-tethered," it can run most applications properly. However, some parts will refuse to operate as expected (e.g.- Safari may crash, you cannot use any programs from Cydia…). |
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| + | But with a '''tethered''' jailbreak, if the device starts back up on its own, it will no longer have a patched kernel, and it may get stuck in a partially started state; in order for it to start completely and with a patched kernel, it essentially must be "re-jailbroken" with a computer (using the "boot tethered" feature of a jailbreaking tool) each time it is turned on. |
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| + | A device with a tethered jailbreak may be able to have a '''semi-tethered''' solution, which means that when the device starts up on its own, it will no longer have a patched kernel (so it will not be able to run modified code), but it will still be usable for normal functions. With a semi-tethered solution, the user can also choose to start the device with the help of the jailbreaking tool in order for it to start with a patched kernel (jailbroken). |
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| + | Tethered jailbreaks require assistance with booting because the device fails one or more signature check along the way due to the jailbreak. The device is able to boot up because there is a way to execute code via USB that allows you to bootstrap to a pwned (no signature check) [[iBSS]], [[iBEC]], or [[iBoot (Bootloader)|iBoot]] to finish the boot process. |
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| + | == Using a tethered (or semi-tethered) jailbreak == |
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| + | To boot tethered, you need to plug your device into a computer, open the software that you used to jailbreak it, and find its tethered boot option. For [[redsn0w]]: click "Extras" and then click "Just boot". |
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| + | If you don't boot tethered when you boot up the device, the device will either be (A) stuck at the Apple logo or (B) boot up into a seemingly "un-jailbroken" state where Cydia, Mail, and Safari crash (and jailbreak-only tweaks/themes don't work) - until you plug the device into a computer, open your tethered boot program (for example redsn0w), and follow its instructions. The situation in (B) is often called a '''semi-tethered jailbreak'''. |
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| + | Tethered jailbreaks behave semi-tethered by default. If you install Mobile Substrate tweaks, your device will still be semi-tethered. But if you install Notification Center plugins that don't depend on WeeLoader, your device will no longer be semi-tethered - unless you also install the [http://thebigboss.org/semitethered-jailbreak BigBoss semitether package]. |
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| + | == Tethered jailbreaks == |
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| + | The initial jailbreak for the [[N72ap|iPod touch 2G]] was tethered, until the hybrid dev team released the [[0x24000 Segment Overflow]]. The codename for the tethered jailbreak was [[redsn0w Lite]]. |
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Revision as of 00:41, 30 September 2013
A device with a tethered jailbreak has to be plugged into a computer while booting up, so that a jailbreaking program (like redsn0w) can help the device boot up jailbroken. It is called a "tethered" jailbreak because your device has to be attached to a computer to boot up properly.
Technical detail
When a device is booting, it loads Apple's own kernel initially, so a jailbroken device must be exploited and have the kernel patched each time it is booted up.
An untethered jailbreak includes powerful enough exploits that if the user turns the device off and back on, the device will start up completely, and the kernel will be patched without the help of a computer – in other words, it will be jailbroken after each reboot.
But with a tethered jailbreak, if the device starts back up on its own, it will no longer have a patched kernel, and it may get stuck in a partially started state; in order for it to start completely and with a patched kernel, it essentially must be "re-jailbroken" with a computer (using the "boot tethered" feature of a jailbreaking tool) each time it is turned on.
A device with a tethered jailbreak may be able to have a semi-tethered solution, which means that when the device starts up on its own, it will no longer have a patched kernel (so it will not be able to run modified code), but it will still be usable for normal functions. With a semi-tethered solution, the user can also choose to start the device with the help of the jailbreaking tool in order for it to start with a patched kernel (jailbroken).
Tethered jailbreaks require assistance with booting because the device fails one or more signature check along the way due to the jailbreak. The device is able to boot up because there is a way to execute code via USB that allows you to bootstrap to a pwned (no signature check) iBSS, iBEC, or iBoot to finish the boot process.
Using a tethered (or semi-tethered) jailbreak
To boot tethered, you need to plug your device into a computer, open the software that you used to jailbreak it, and find its tethered boot option. For redsn0w: click "Extras" and then click "Just boot".
If you don't boot tethered when you boot up the device, the device will either be (A) stuck at the Apple logo or (B) boot up into a seemingly "un-jailbroken" state where Cydia, Mail, and Safari crash (and jailbreak-only tweaks/themes don't work) - until you plug the device into a computer, open your tethered boot program (for example redsn0w), and follow its instructions. The situation in (B) is often called a semi-tethered jailbreak.
Tethered jailbreaks behave semi-tethered by default. If you install Mobile Substrate tweaks, your device will still be semi-tethered. But if you install Notification Center plugins that don't depend on WeeLoader, your device will no longer be semi-tethered - unless you also install the BigBoss semitether package.
Tethered jailbreaks
The initial jailbreak for the iPod touch 2G was tethered, until the hybrid dev team released the 0x24000 Segment Overflow. The codename for the tethered jailbreak was redsn0w Lite.
