UPDATE: Apple latest firmware is iOS 5.1.1. Apple has stopped signing all other firmwares, including iOS 5.0.1, iOS 4.3.3 and iOS 4.3.5. This means you can NOT restore to 5.0.1/4.3.3/4.3.5 any more (both original and custom), unless you have saved your SHSH keys for it.
If you have decided to perform an untethered jailbreak and unlock, you need to get the following information:
What type of device do you have (iPhone 3G/3GS/4, iPod Touch 3G/4G, iPad 1/2, Apple TV)?
Do you need unlock (if your iPhone locked to one carrier and you want to use it with another)?
The answer is NO, if the device is not iPhone, if it was purchased as factory unlocked and can be used with any cellular carrier (f.e. in Canada, France, etc).
If the answer is YES, you need to find out your modem version (Setting-General-About-Modem).
What firmware version do you have? Take a look at Setting-General-About-Version. For example it could be iOS 4.3.3.
What operating system do you use on your desktop (Windows, Mac OS)?
How to perform jailbreak, when you do NOT need an unlock
For iPhone 3G the latest is iOS 4.2.1. You can perform jailbreak with any utility. For iOS 4.2.1 you can also use them or GreenPois0n (Windows, Mac OS).
iPad 2 jailbreak is available only for iOS 4.3.3 via JailbreakMe and and iOS 5.0.1 via Absenthe.
iPhone 4S jailbreak is available for iOS 5.0 / iOS 5.0.1 via Absenthe.
Apple stopped signing iOS 4.3.3, so you cannot update to iOS 4.3.3 without SHSH keys saved (in advance some time ago). If you have iPhone 4, iPhone 3GS, iPad 1, iPod Touch 3G or iPod Touch 4G that run iOS 4.3.3 – use JailbreakMe or RedSn0w to untether jailbreak your device.
If you have saved SHSH keys for iOS 4.3.3 you can use PwnageTool (Mac OS) or Sn0wBreeze (Windows).
For iOS 4.3.4/4.3.5 only tethered jailbreak is possible with redsn0w. Tethered means that each time you restart your device you will have to connect it to a computer and run redsn0w. The untethered iOS 4.3.5 jailbreak is possible only for iPhone 3GS with old bootrom. You can detect your bootrom version using this tutorial.
To jailbreak and unlock iOS 5 use latest version of redsn0w 0.9.9 or sn0wbreeze 2.8. You can jailbreak tethered or semi-tethered.
The untethered iOS 5 jailbreak is possible only for iPhone 3GS with old bootrom. You can detect your bootrom version using this tutorial.
For iPhone 4/3GS, iPad 1, iPod Touch 3G/4G an untethered jailbreak is available for iOS 5.0.1. For untethered jailbreak use the latest redsn0w 0.9.10 or Corona – package from Cydia to untether currently installed tethered jailbreak.
Tutorial how to untether installed tethered jailbreak is available here.
For iPhone 4S and iPad 2 use Absenthe.
For tethered iOS 5.0.1 jailbreak you an use redsn0w 0.9.9 and sn0wbreeze 2.8.
iOS 5.1 / iOS 5.1.1
For now only tethered jailbreak is available for iPhone 4/3GS, iPad 1 and iPod Touch 3G/4G for iOS 5.1 and iOS 5.1.1.
New redsn0w is.gd/6eek4Y explicitly supports iOS5b7 (no need to point at b6 IPSW). Also brings back old-bootrom 3GS goodies.
This is great news for both developers and owners of old bootrom iPhone 3GS’s who accidentally updated to iOS 4.3.5.
About 12 hours after we released redsn0w 0.9.8b7 with some improvements for iOS5b6, Apple went and released iOS5b7 (what are the odds of that?!?). Even though that redsn0w could still jailbreak iOS5b7, you needed to point it at the iOS5b6 IPSW to do so. Today’s redsn0w 0.9.8b7b lets you point redsn0w directly at the iOS5b7 IPSW instead.
We’ve also added some overall improvements for old-bootrom 3GS owners (where the 24kpwn exploit applies): on those devices, you can tell redsn0w to untether 4.3.5 and lower, or iOS5b7. Old-bootrom 3GS owners can once again choose custom logos, and/or verbose booting (for the really nerdy iPhone3GS fans out there!). And it allows 4.3.4 or 4.3.5 users to use ultrasn0w again (if they have a compatible baseband).
Last but not least, we fixed some lingering Verizon iPhone4 4.2.10 JB issues.
iH8Sn0w released Sn0wBreeze 2.8b7, which adds jailbreak support for the latest iOS 5 beta 7 firmware.
Sn0wBreeze creates custom firmware and allows users to preserve baseband for unlock (ultrasn0w doesn’t work with iOS 5 yet). This new version also adds hacktivation and removes UDID developer check. This means that you can try iOS 5 without developer account from Apple.
You can download Sn0wBreeze 2.8b7 for Windows here.
sn0wbreeze v2.8b7 – Release Notes
* Now jailbreaks iOS 5 beta 7.
* Still removes UDID Developer check + Beta timer.
* Still has the ability to hacktivate.
* Still preserves the baseband (as always!).
* iPhone 3GS (old bootrom)…..NO
* iPhone 3GS (new bootrom)….YES
* iPhone 4 (GSM)…………..YES
* iPhone 4 (CDMA)………….YES
* iPod Touch 3G……………YES
* iPod Touch 4…………….YES
* iPad 1G…………………YES
** REMEMBER TO BOOT WITH “iBooty” **
The iPhone Dev-Team has released RedSn0w 0.9.8b3 which can perform a tethered jailbreak on iOS 4.3.4. This means that you will have to connect your device to a computer and run redsn0w each time you restart.
For the convenience of kernel hackers like @comex and @i0n1c, we have a new redsn0w 0.9.8b3 that supports a TETHERED jailbreak for iOS 4.3.4 on all devices that have 4.3.4 except the iPad2. The vast majority of people will want to stay back at 4.3.3 because that’s where the untethered jailbreak is! There are no new features in 4.3.4 – only fixes for jailbreak exploits.
Also, this is a good time to remind everyone (since we’re still seeing confusion about this): iPad2 owners with a baseband (3G or CDMA) cannot currently use saved blobs to go back to 4.3.3 once the signing window is closed. This is unlike every other device, so don’t be confused! iPad2 owners with basebands should stay away from all updates to maintain your jailbreak!
This jailbreak works with iPhone 3GS, iPhone 4, iPad 1, iPod Touch 3G and iPod Touch 4G. It does not work with iPad 2.
You can download RedSn0w 0.9.8b3 from here: (Mac, Windows)