In more detail: Each i OS device has a bootchain that tries to make sure only trusted/signed code is loaded.

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In the past, you'd have to backup your device, install the Apple update (which removes jailbreak), jailbreak your device again, and restore from a backup. Even bigger if you forgot to backup all of your customizations.

Thankfully, i OS hacker/engineer Ryan Petrich feels our pain.

However, rather than having to run a tool from a computer to apply the kernel patches, the user is able to re-jailbreak their device with the help of an app (usually sideloaded using Cydia Impactor) running on their device.

In the case of the i OS 9.2-9.3.3 jailbreak, a Safari-based exploit was available, thereby meaning a website could be used to rejailbreak.

An untethered jailbreak uses exploits that are powerful enough to allow the user to turn their device off and back on at will, with the device starting up completely, and the kernel will be patched without the help of a computer – in other words, it will be jailbroken even after each reboot. 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.

He released his SSLPatch tweak, which lets you simply install the patch from Cydia without having to backup and re-jailbreak.

This does not update you to i OS 7.0.6, but only fixes the security issues.

Cydia is most important thing for jailbreak i OS user.

It allows to install many value added free apps on jailbroken i Phone, i Pad, i Pad mini and i Pod Touch.

This was later updated to create a new service (AFC2) that allows access to the full filesystem.