Jailbreak

Jailbreaking is the process by which full execute and write access is obtained on all the partitions of the Apple TV, iPad, iPad mini, iPhone or iPod touch. It is done by patching /private/etc/fstab to mount the System partition as 'read-write'. This is entirely different from an unlock. Jailbreaking is the first action that must be taken before things like unofficial activation (hacktivation), and unofficial unlocking can be applied.

The original jailbreak also included modifying the AFC service (used by iTunes to access the filesystem) to give full filesystem access from root. This was later updated to create a new service (AFC2) that allows access to the full filesystem.

Modern jailbreaks also include patching the kernel to get around code signing and other restrictions. These are called Kernel Patches.

Version numbers are the first to jailbreak and last is the last supported version. Last will only be listed if a newer version is out that does not support the device and iOS.

Note: The legality of jailbreaking your device varies with each country/region. Wikipedia has a summary of legality for some countries.

Note: Beta Firmwares are not listed here.

2.x
1 Only applicable for devices with the old bootrom.

3.x
1 An earlier version of Cydia is installed. 2 Only applicable for devices with the old bootrom. 3 Only applicable for devices with the old bootrom. Requires the device to have signature checks disabled (pwned).

4.x
1 Tethered jailbreak on devices with the new bootrom. 2 Only applicable for devices with the old bootrom. 3 Requires an unofficial firmware bundle.

Apple TV
Note: "Marketing Version" is the version that the Apple TV reports in its "About" screen. 1 No package management GUI. 2 User needs to manually add PwnageTool firmware bundle into application.

5.x
1 Requires an unofficial PwnageTool bundle.

Apple TV
Note: "Marketing Version" is the version that the Apple TV reports in its "About" screen. 1 No package management GUI.

6.x
1 Tethered jailbreak on devices not vulnerable to 0x24000 Segment Overflow. Upgradable to untethered jailbreak via evasi0n Cydia package. 2 Tethered jailbreak on devices not vulnerable to 0x24000 Segment Overflow. Requires pointing to 6.0 IPSW. Upgradable to untethered jailbreak via evasi0n Cydia package. 3 Tethered jailbreak on devices not vulnerable to 0x24000 Segment Overflow. Requires pointing to 6.0 IPSW. Upgradable to untethered jailbreak via p0sixspwn Cydia package. 4 Tethered jailbreak on devices not vulnerable to 0x24000 Segment Overflow. Upgradable to untethered jailbreak via p0sixspwn Cydia package.

Apple TV
Note: "Marketing Version" is the version that the Apple TV reports in its "About" screen. 1 Tethered jailbreak. 2 Point at 6.0 IPSW. Also Tethered jailbreak.

7.x
1 Build 11A466. Requires a hex edit of evasi0n7 binary. See this image. 2 Semi-tethered jailbreak 3 Tethered jailbreak. "Upgradable" to semi-tethered with "GeekSn0w Semi Untether Payload" from geekrepo.beiphone.it. 4 Requires using an unofficial fix.

Apple TV
Note: "Marketing Version" is the version that the Apple TV reports in its "About" screen.

8.x
1 SSH only. 2 iPad4,7 (Wi-Fi) only. Note: Pangu8 is broken ("unable to get resources")

Apple TV
Note: "Marketing Version" is the version that the Apple TV reports in its "About" screen.

Apple TV (tvOS)
Note: "Marketing Version" is the version that the Apple TV reports in its "About" screen.