Jailbreak (S5L8920+)

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When the iPhone 3GS was initially released, Apple did not have enough time to fix the 0x24000 Segment Overflow in the S5L8920. However, in order to flash an exploited LLB and jailbreak the iPhone 3GS, one of the following needed to be done:

  • Find a new iBoot exploit every time a new firmware is out.
  • Find a way to bypass the ECID checks.
  • Use a bootrom exploit that allows unsigned code execution via USB.

Newer devices (iPhone 3GS with new bootrom, iPod touch 3G, and subsequent devices) are no longer vulnerable to the 0x24000 Segment Overflow exploit. Many of them are susceptible to geohot's bootrom exploit (originally found in limera1n), which allows unsigned code execution over USB. Even newer devices, starting with the iPad 2, have no bootrom exploits to run unsigned code at all.

ECID

Apple added a new tag to the IMG3 File Format called ECID. The ECID is unique to each phone, and its signature is being checked. With this method, Apple attempts to block downgrades once newer firmware becomes available, unless you have a dump of your old firmware's unique IMG3 or signed certificate. Therefore, iBoot exploits won't be so useful for tethered jailbreaks, because such exploits will be closed in new firmwares. [1].

The issue with this is that, even with the 0x24000 Segment Overflow still in bootrom, an iBoot exploit was still needed to actually flash the exploited LLB. Apple uses this ECID stuff to block downgrading iBoot to a vulnerable version. It was resolved when Geohot released his limera1n tool, which used a bootrom exploit to upload an unsigned iBoot. Still the problem remains with newer devices with 0x24000 fixed - tampering with firmware makes such jailbreak tethered unless some other exploit is used.

There are methods to help keep your downgrading ability, though.

  • If it was cached prior to 3.1's release, 3GS owners were able save a file which contains the signature of the 3.0 iBSS containing their ECID, using the purplera1n website. A tool has not been created to incorporate this file into a fully signed iBSS, however.
  • Saurik's servers are actively caching the necessary files. Instructions to use the servers are included.
  • The SHSH associated with an ECID can be also saved by running TinyUmbrella. TinyUmbrella allows the user to restore to whatever version is associated with that SHSH file permanently. This is based on the aforementioned service Saurik provides remotely from his server(s).

Jailbreak tools

Apple TV 2G

NOTE: The version in parentheses is what the Apple TV reports on TV.

Jailbreak Tool Works with firmware...
4.1 (4.0) 4.2 (4.1) 4.2.1 (4.1.1) 4.3 Build 8F191m (4.2) 4.3 Build 8F202 (4.2.1)
redsn0w No No No No No
limera1n no package management GUI No No No No
sn0wbreeze no package management GUI No No No No
greenpois0n no package management GUI No RC6 No No
PwnageTool no package management GUI Restore from a custom firmware with unofficial bundle1 4.2 No No
Seas0nPass No No Yes No No

1 Tethered jailbreak.

iPad

Jailbreak Tool Works with firmware...
3.2 3.2.1 3.2.2 4.2.1 4.3 4.3.1
Spirit Yes No No No No No
Star Yes Yes No No No No
limera1n No No Yes No No No
greenpois0n No No RC4 and earlier RC5 No No
redsn0w No No 0.9.6b2 0.9.6rc81 or 0.9.7b61 2 No No
PwnageTool No No 4.1-4.1.3 4.2 No No
sn0wbreeze No No 2.1 2.2 No No

1 Tethered jailbreak.

2 If SHSHs were saved for iOS 4.2b3 and if you have a developer access to its IPSW, Jailbreak Monte can be used.

iPad 2

Jailbreak Tool Works with firmware...
4.3 4.3.1

iPhone 3GS

Jailbreak Tool Works with firmware...
3.0 3.0.1 3.1 3.1.2 3.1.3 4.0 4.0.1 4.0.2 4.1 4.2.1 4.3 4.3.1
purplera1n Yes No No No No No No No No No No No
redsn0w 0.8 0.8 0.9.21 or 0.9.31 0.9.21 or 0.9.31 No No No No 0.9.6b2 0.9.6rc81 No No
blackra1n No No Yes1 Yes1 No No No No No No No No
Spirit No No No Yes Yes No No No No No No No
Star No No No Yes Yes Yes Yes No No No No No
PwnageTool No No Restore from a custom firmware2 3.1.42 Restore from a custom firmware2 Restore from a custom firmware with unofficial firmware bundle2 4.1-4.1.3 4.2 No No
sn0wbreeze No No No 1.42 or 2.0.21 2 1.5.12 or 2.0.21 2 1.71 2 or 2.0.21 2 2.0.21 2 2.1 2.2 No No
limera1n No No No No No Yes Yes Yes Yes No No No
greenpois0n No No No No No No No No RC4 and earlier RC5 No No

1 Tethered jailbreak on devices with the new bootrom.

2 Only applicable for devices with the old bootrom. Requires the device to have signature checks disabled (pwned).

3 Requires an unofficial firmware bundle.

iPhone 4 (GSM model)

Jailbreak Tool Works with firmware...
4.0 4.0.1 4.0.2 4.1 4.2.1 4.3 4.3.1
Star Yes Yes No No No No No
limera1n Yes Yes Yes Yes No No No
greenpois0n No No No RC4 and earlier RC5 No No
redsn0w No No No 0.9.6b2 0.9.6rc81 or 0.9.7b61 2 No No
PwnageTool No No No 4.1-4.1.3 4.2 No No
sn0wbreeze No No No 2.1 2.2 No No

1 Tethered jailbreak.

2 If SHSHs were saved for iOS 4.2b3 and if you have a developer access to its IPSW, Jailbreak Monte can be used.

iPhone 4 (CDMA model)

Jailbreak Tool Works with firmware...
4.2.5 4.2.6
greenpois0n No RC5 b4
PwnageTool No 4.2
sn0wbreeze No 2.2

iPod touch 3G

Jailbreak Tool Works with firmware...
3.1.1 3.1.2 3.1.3 4.0 4.0.2 4.1 4.2.1 4.3 4.3.1
blackra1n Yes1 Yes1 No No No No No No No
redsn0w 0.9.21 or 0.9.31 0.9.21 or 0.9.31 No No No 0.9.6b2 0.9.6rc81 No No
Spirit No Yes Yes No No No No No No
Star No Yes Yes Yes No No No No No
sn0wbreeze No 2.0.21 2.0.21 1.71 or 2.0.21 2.0.21 2.1 2.2 No No
limera1n No No No Yes Yes Yes No No No
greenpois0n No No No No No RC4 and earlier RC5 No No
PwnageTool No No No No No 4.1-4.1.3 4.2 No No

1 Tethered jailbreak.

iPod touch 4G

Jailbreak Tool Works with firmware...
4.1 (both builds) 4.2.1 4.3 4.3.1
limera1n Yes No No No
redsn0w 0.9.4b2 0.9.6rc81 or 0.9.7b61 2 No No
greenpois0n RC4 and earlier RC5 No No
PwnageTool 4.1-4.1.3 4.2 No No
sn0wbreeze 2.1 2.2 No No

1 Tethered jailbreak.

2 If SHSHs were saved for iOS 4.2b3 and if you have a developer access to its IPSW, Jailbreak Monte can be used.