View source for Jailbreak (S5L8920+)

When the [[N88ap|iPhone 3GS]] was initially released, Apple did not have enough time to fix the [[0x24000 Segment Overflow]] in the [[S5L8920 (Bootrom)|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.
* Find another bootrom exploit that allows unsigned code executing via USB ([[Pwnage 2.0]]-like)

This also applies to the iPhone 3GS with [[iBoot-359.3.2|the new bootrom]], [[N18ap|iPod touch 3G]] and later devices, except a bootrom exploit 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. [http://iphonejtag.blogspot.com/2009/06/ecid-field-downgrades-no-dice.html].

The issue with this is that, even with the [[0x24000 Segment Overflow]] still in bootrom, an [[iBoot]] exploit is still needed to actually flash the exploited [[LLB]].  Apple uses this ECID stuff to block downgrades, and a new [[iBoot]] exploit is needed whenever they fix the last, so that the 0x24000 Segment Overflow can be applied. This is because Apple chooses to not let you upload an older, exploitable [[iBEC]]/[[iBoot]]/[[iBSS]] to the device (unless it is signed with your ECID).

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 [http://purplera1n.com/ 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. [http://www.saurik.com/id/12#howto 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==
===[[K48ap|iPad]]===
{| class="wikitable sortable" style="font-size: smaller; text-align: center; table-layout: fixed; border-collapse: collapse;" border="1"
|-
!rowspan="2"| [[Jailbreak]] Tool
!colspan="2"| Works with [[firmware]]...
|-
|style="width:100px;"| 3.2?
|style="width:100px;"| 3.2.1?
|-
| [[Spirit]]
| {{yes}}
| {{no}}
|-
| [[Jailbreakme]]
| {{yes}}
| {{yes}}
|}

===[[N88ap|iPhone 3GS]]===
{| class="wikitable sortable" style="font-size: smaller; text-align: center; table-layout: fixed; border-collapse: collapse;" border="1"
|-
!rowspan="2"| [[Jailbreak]] Tool
!colspan="9"| Works with [[firmware]]...
|-
|style="width:100px;"| 3.0?
|style="width:100px;"| 3.0.1?
|style="width:100px;"| 3.1?
|style="width:100px;"| 3.1.2?
|style="width:100px;"| 3.1.3?
|style="width:100px;"| 4.0?
|style="width:100px;"| 4.0.1?
|-
| [[purplera1n]]
| {{yes}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
| {{no}}
|-
| [[redsn0w]]
| {{yes|0.8}}
| {{yes|0.8}}
| {{yes|0.9.2<sup>1</sup> or 0.9.3<sup>1</sup>}}
| {{yes|0.9.2<sup>1</sup> or 0.9.3<sup>1</sup>}}
| {{no}}
| {{no}}
| {{no}}
|-
| [[PwnageTool]]
| {{no}}
| {{no}}
| {{partial|Restore from a custom firmware<sup>2</sup>}}
| {{yes}}
|colspan="3" {{partial|Restore from a custom firmware<sup>2</sup>}}
|-
| [[blackra1n]]
| {{no}}
| {{no}}
| {{yes|Yes<sup>1</sup>}}
| {{yes|Yes<sup>1</sup>}}
| {{no}}
| {{no}}
| {{no}}
|-
| [[Spirit]]
| {{no}}
| {{no}}
| {{no}}
| {{yes}}
| {{yes}}
| {{no}}
| {{no}}
|-
| [[Jailbreakme]]
| {{no}}
| {{no}}
| {{no}}
| {{yes}}
| {{yes}}
| {{yes}}
| {{yes}}
|}
<sup>1</sup> Tethered jailbreak on devices with the [[iBoot-359.3.2|new bootrom]].

<sup>2</sup> Only applicable for devices with the [[iBoot-359.3|old bootrom]]. Requires the device to have signature checks disabled (pwned).

===[[N90ap|iPhone 4]]===
{| class="wikitable sortable" style="font-size: smaller; text-align: center; table-layout: fixed; border-collapse: collapse;" border="1"
|-
!rowspan="2"| [[Jailbreak]] Tool
!colspan="2"| Works with [[firmware]]...
|-
|style="width:100px;"| 4.0?
|style="width:100px;"| 4.0.1?
|-
| [[Jailbreakme]]
| {{yes}}
| {{yes}}
|}

===[[N18ap|iPod touch 3G]]===
{| class="wikitable sortable" style="font-size: smaller; text-align: center; table-layout: fixed; border-collapse: collapse;" border="1"
|-
!rowspan="2"| [[Jailbreak]] Tool
!colspan="4"| Works with [[firmware]]...
|-
|style="width:100px;"| 3.1.1?
|style="width:100px;"| 3.1.2?
|style="width:100px;"| 3.1.3?
|style="width:100px;"| 4.0?
|-
| [[blackra1n]]
| {{yes|Yes<sup>1</sup>}}
| {{yes|Yes<sup>1</sup>}}
| {{no}}
| {{no}}
|-
| [[redsn0w]]
| {{yes|0.9.2<sup>1</sup> or 0.9.3<sup>1</sup>}}
| {{yes|0.9.2<sup>1</sup> or 0.9.3<sup>1</sup>}}
| {{no}}
| {{no}}
|-
| [[Spirit]]
| {{no}}
| {{yes}}
| {{yes}}
| {{no}}
|-
| [[Jailbreakme]]
| {{no}}
| {{yes}}
| {{yes}}
| {{yes}}
|}
<sup>1</sup> Tethered jailbreak.