The full (untethered) jail iOS 4.2.1 for iPhone 4, iPhone 3GS, iPod touch 3G, iPod touch 4G and iPad - Greenpois0n

• Updating iTunes to the latest version, iTunes 10.1 can be downloaded HERE
  
• Install iOS 4.2.1 on your iPhone, (preferably set as " NEW ")
  
• We begin jailbreak with RedSn0w
  
  How to download from FILE EXCHANGERS
  
  Download Redsn0w 0.9.6rc8 For Windows HERE
  Download Redsn0w 0.9.6rc8 For Mac HERE
  
  
• Download the official iOS 4.2.1 via iTunes , or HERE
  
  ITunes stores downloaded firmware along this path:
  
  • For Windows XP C: \ Documents and Settings \ username \ Application Data \ Apple Computer \ iTunes \ iPhone Software Updates
    
  • For Windows Vista Start \ username \ AppData \ Roaming \ Apple Computer \ iTunes \ iPhone Software Updates
    
  • For Windows 7 Start \ username \ AppData \ Roaming \ Apple Computer \ iTunes \ iPhone Software Updates
    
  • For Mac OSX \ username \ Libraries \ iTunes \ iPhone Software Updates
  
  
• Close iTunes !!!
  Run RedSnow (on Win 7 run with Administrator rights and compatibility mode with XP SP3 ). Click Browse and in the window that opens select iOS 4.2.1 firmware
  
• Click Next . To continue, Redsn0w recommends turning off the phone (hold the Power button on the phone and navigate the slider that appears).
  
  Use the checkboxes to select the required components:
  
  
  • Install Cydia - Fill in the Cydia installer device. Without this, the Jail loses 90% of its meaning;
    
  • Verbose boot - text loading mode . When you start the device instead of an apple, you will see diagnostic messages on a black background. For an ordinary user (and for a non-regular user too) this option is unnecessary;
    
  • Install iPad baseband - installation of a modem from the iPad (06.15.00) , which can be unlocked using Ultrasn0w 1.2 (the old modem can not be returned !!! );
    
  • Custom boot logo - the ability to replace the bullseye when uploaded to any other image. When installing a checkmark, a window appears immediately in which you need to specify a graphic file to be replaced (only PNG, preferably 320-480 and not more than 100KB of weight);
    
  • Custom recovery logo - the ability to replace the iTunes logo and the lanyard, which are displayed when the device starts in recovery mode, on any other picture. Requirements are the same as for boot logo;
    
  • Enable multitasking (option is visible only for iPhone 3G and iPod Touch 2G) - activation of multitasking at the price of a strong braking system;
    
  • Enable homecreen wallpaper (the option is visible only for iPhone 3G and iPod Touch 2G) - activation of background images of desktops. It also leads to slowdowns;
    
  • Enable battery percentage (option is visible only for iPhone 3G and iPod Touch 2G) - activates the display of the battery charge in percent. Unlike the previous two options, it does not lead to negative consequences (To enable: Settings -> basic -> statistics -> battery charge);
    
  • Just boot tethered right now - the option is useful only when your device refuses to turn on after reboot. Selecting this option removes all the upper checkboxes;
    
  • Just enter pwned DFU mode right now - the option is needed if you just need to enter the device into DFU mode. Selecting this option removes all the upper checkmarks.
  
  * Include wallpaper and multitasking on the iPhone 3G and iPod Touch 2G NOT recommend (since it lacks the hardware resources of this phone)
  
  
• Click Next ,
  Next, you need to transfer the phone to DFU mode , following the instructions on the screen:
  
  • Hold the Power button for 3 seconds .
    
  • Without releasing the Power button, press the Home button for 10 seconds .
    
  • Let's release the Power button, but continue to keep Home 30 seconds .
    
  • After the appearance of a white screen, release both buttons.
  
  
• It remains only to wait a little (on the phone screen appears the message Downloading Jailbreak Data ..., then running "Pineapple", after the jailbreak the phone will reboot). If Redsn0w is out, then just repeat step 7 .
  
• If the Cydia label is displayed in white , then repeat step 5 , in step 6, tick only the " Just boot tethered right now " item, after the Jail is completed, we get the working version of Cydia .
  Do not forget to go to Cydia and install all the updates:

• Do not run Cydia while on your phone there is no connection to the Internet, EDGE or WiFi .
  
• Check, or configure the Internet connection, and then run Cydia .
  
• The reorganization of Cydia will begin. Wait until Cydia closes itself after the reorganization, and you will be thrown to the desktop.
  
• Run Cydia again (to the question Who Are You? Answer Hacker (+ Command Line) ) and you will see important updates for Cydia , install them ( Complete Upgrade )

• Disable wallpaper
  
• Disable multitasking
  
• Disable Spotlight search (settings - basic - home button - search Spotlight - uncheck all the checkboxes and reboot)
  
• From time to time restart the phone with the help of holding the Home and Power buttons for 10 seconds, until the phone turns off

• Run the Redsn0w file on behalf of the Administrator and the compatibility mode with XP SP2 / 3 .
  
• Probably, the firmware file is not completely downloaded. Download firmware .ipsw again or from an alternative source.
  
• Redsn0w on some configurations may hang because of the use of multi-core processors. Open " Task Manager ", in the " processes " find " Redsn0w.exe ", in the context menu select " Set compliance ... / SetAffinity ", leave a tick only for " CPU0 / CPU0 ".

• No! Subscription to SHSH-certificates below iOS 4.2.1 is already closed, more details here .
  Unattached jailbreak for iPhone 4, iPhone 3GS (New boot), iPod Touch 2G, iPod Touch 3G, iPod Touch 4G, iPad Greenpois0n

• Follow the 9th paragraph of the instruction
  
• Firmly reinstall the device, following the instructions in the instructions

• What error code means can be found in the corresponding forum thread
  
• Or on the Apple website

• Most likely, your device does not support untethered Jailbreak.
  With each shutdown (or full discharge), the device will have to connect it to a computer with Redsn0w installed and go through the entire hacking procedure (leaving only the " Just boot tethered right now " option)
  Unattached jailbreak for iPhone 4, iPhone 3GS (New boot), iPod Touch 2G, iPod Touch 3G, iPod Touch 4G, iPad Greenpois0n

• By serial number of the device ( Settings -> General -> About the device )
  Example: 87022Z635NQ
  We are interested in the 3rd 4th and 5th digits:
  Xx 022 xxxxxx
  The third digit is the year (" 9 " -2009, " 0 " -2010)
  4,5- th figures a week - until the 40th week of 2009 BootRoom old
  Above the 41st week of 2009. Or the whole of 2010, BootRoom is new !
  If you have a borderline week (40-41), it's better to use the program described below.
  
• Using the program iDetector
  
  
  
  • Download iDetector
    
  • If Java is not installed, then go to java.com, download and install the latest version
    
  • Translate the phone into DFU mode (7th instruction point)
    
  • Run iDetector, click on the button, learn the version of bootrom
    
  • To exit the DFU, press the Home + power button again.

• No, the modem version does not go down!

• Modem version 06.15.00 has a version above any of the modems of all currently released firmware 3G and 3GS phones, and therefore updating phones with factory firmware via iTunes of your phone will result in error number 1015 , and the phone will remain in " recovery " mode ) From which to pull it out will not be so easy.
  And so you already have a modem 06.15.00, the phone is jailbroken and you want to restore the firmware, for this we follow these simple steps:
  
  
  • A ) if you use PwnageTool to jailbreak, then use this utility to create a custom firmware version 4.1 or 4.2.1 , when the program asks you about the installation of a BB (modem) 06.15.00, you should refuse it . Complete the creation of custom firmware and use iTunes to flash the phone.
    
  • B ) If you use RedSn0w , then you have two options:
    
    • B-1 ) if you already have the iOS 4.1 firmware, then flashing it again on iOS 4.1 , and when the window with error # 1015 appears on the screen, start Tiny Unbrella and output the phone from the recovery mode. After that, run Redsn0w , follow its instructions, and when you get to the set of checkmarks, DO NOT note the installation of the modem 06.15.00 . You already have it.
      
    • B-2 ) if you already have iOS 4.2.1 , then you need to flash on iOS 4.1 (because iOS 4.2.1 does not allow you to get the phone out of the " recovery " mode, because it already has a stupid check on it Correspondence modem / OS, i.e., for example, for iPhone 3G, iOS 4.2.1 the modem should be 05.15.02 and no other), well, then follow the instructions from point B-1 . If you want to flash firmware 4.2.1 , then you have only one way out - to create custom firmware according to the instructions of point A , there are no other methods at the moment.