Difference between revisions of "Tethered jailbreak"

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(There's no need to make a special mention for redsn0w 0.9.6b4.)
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A '''tethered jailbreak''' is only able to temporarily jailbreak the device during a single boot. If the user turns the device off and then boots it back up without the help of a jailbreak tool, the device will no longer be running a patched kernel, and it may get stuck in a partially started state, such as [[Recovery Mode]]. In order for the device to start completely and with a patched kernel, it must be "re-jailbroken" with a computer (using the "boot tethered" feature of a tool) each time it is turned on. All changes to the files on the device (such as installed package files or edited system files) will persist between reboots.
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.
 
   
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== Using a tethered jailbreak ==
==[[N72ap|iPod touch 2G]]==
 
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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To boot tethered, their user must plug the device into a computer and run the jailbreak tool to "boot tethered".
   
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If a user attempts to boot the device without using a computer, the device will either be stuck at the Apple logo, in [[Recovery Mode]], or in a seemingly "un-jailbroken" state where [[Cydia.app|Cydia]], Mail, and Safari crash (and jailbreak-only tweaks/themes don't work) - until you boot tethered.
==Linux==
 
Currently, certain devices are capable of booting to Linux. The downside is that this is a tethered boot.
 
   
== Explanation ==
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== Tethered exploits ==
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The [[limera1n Exploit]] and other [[bootrom]] exploits can be used to tethered jailbreak older devices on any iOS version, because bootrom exploits take advantage of code that is permanently embedded in the device's hardware, which Apple cannot update with iOS updates. Those tools do usually need minor software updates (not exploit-related) to explicitly support new iOS versions. They also use additional exploits (specific to each iOS version) to produce untethered jailbreaks when possible.
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 to finish the boot process.
 
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The initial jailbreak for the [[N72AP|iPod touch (2nd generation)]] 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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==See Also==
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*[[Jailbreak]]
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*[[Jailbreak Exploits]]
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*[[Untethered jailbreak]]
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*[[Semi-tethered jailbreak]]
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*[[Semi-untethered jailbreak]]
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[[Category:Jailbreaking]]

Latest revision as of 09:26, 26 March 2017

A tethered jailbreak is only able to temporarily jailbreak the device during a single boot. If the user turns the device off and then boots it back up without the help of a jailbreak tool, the device will no longer be running a patched kernel, and it may get stuck in a partially started state, such as Recovery Mode. In order for the device to start completely and with a patched kernel, it must be "re-jailbroken" with a computer (using the "boot tethered" feature of a tool) each time it is turned on. All changes to the files on the device (such as installed package files or edited system files) will persist between reboots.

Using a tethered jailbreak

To boot tethered, their user must plug the device into a computer and run the jailbreak tool to "boot tethered".

If a user attempts to boot the device without using a computer, the device will either be stuck at the Apple logo, in Recovery Mode, or in a seemingly "un-jailbroken" state where Cydia, Mail, and Safari crash (and jailbreak-only tweaks/themes don't work) - until you boot tethered.

Tethered exploits

The limera1n Exploit and other bootrom exploits can be used to tethered jailbreak older devices on any iOS version, because bootrom exploits take advantage of code that is permanently embedded in the device's hardware, which Apple cannot update with iOS updates. Those tools do usually need minor software updates (not exploit-related) to explicitly support new iOS versions. They also use additional exploits (specific to each iOS version) to produce untethered jailbreaks when possible.

The initial jailbreak for the iPod touch (2nd generation) was tethered, until the hybrid dev team released the 0x24000 Segment Overflow. The codename for the tethered jailbreak was redsn0w Lite.

See Also