Jailbreak (S5L8920+)

From The iPhone Wiki
Revision as of 12:30, 2 November 2010 by Redart (talk | contribs) (ECID: Typo)
Jump to: navigation, search

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 needs 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 (2 of them were finally found by Geohot and Chronic Dev Team).

This also applies to the iPhone 3GS with the new bootrom, iPod touch 3G and later devices, except a bootrom exploit for the normal boot-chain or a library based jailbreak payload (similar to Star) is needed as well.

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 was resolved when Geohot released his limera1n tool exploiting bootrom security hole which allowed him to upload 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).

Release of PwnageTool 4.1.2 makes storing SHSHs unnecessary for the time being - there is always a way now for all current iDevices to rollback to jailbroken 4.1 firmware.

Jailbreak tools

iPad

Jailbreak Tool Works with firmware...
3.2 3.2.1 3.2.2
Spirit Yes No No
Star Yes Yes No
limera1n No No Yes
greenpois0n No No Yes
redsn0w No No 0.9.6b2
PwnageTool No No 4.1

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
purplera1n Yes 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
blackra1n No No Yes1 Yes1 No No No No No
Spirit No No No Yes Yes No No No No
Star No No No Yes Yes Yes Yes No No
PwnageTool No No Restore from a custom firmware2 3.1.4 Restore from a custom firmware2 Restore from a custom firmware with unofficial bundle2 4.1
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
limera1n No No No No No Yes Yes Yes Yes
greenpois0n No No No No No No No No Yes

1 Tethered jailbreak on devices with the new bootrom. Requires usage of the usb_control_msg(0x21, 2) Exploit.

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

iPhone 4

Jailbreak Tool Works with firmware...
4.0 4.0.1 4.0.2 4.1
Star Yes Yes No No
limera1n Yes Yes Yes Yes
greenpois0n No No No Yes
redsn0w No No No 0.9.6b2
PwnageTool No No No 4.1

iPod touch 3G

Jailbreak Tool Works with firmware...
3.1.1 3.1.2 3.1.3 4.0 4.0.2 4.1
blackra1n Yes1 Yes1 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
Spirit No Yes Yes No No No
Star No Yes Yes Yes No No
sn0wbreeze No 2.0.21 2.0.21 1.71 or 2.0.21 2.0.21
limera1n No No No Yes Yes Yes
greenpois0n No No No No No Yes
PwnageTool No No No No No 4.1

1 Tethered jailbreak. Requires usage of the usb_control_msg(0x21, 2) Exploit.

iPod touch 4G

Jailbreak Tool Works with firmware...
4.1
limera1n Yes
greenpois0n Yes
PwnageTool 4.1