How to Update iPhone 3g/3gS & iPhone 4 to Custom iOS 4.2.1 Preserving your Baseband

This video describes how to update your iPhone 3g/ 3gS or iPhone 4 from any firmware lower than 4.2.1 to a Custom 4.2.1 Firmware. It could be 3.0, 3.1, 3.1.2, 3.1.3, 4.0, 4.0.1, 4.0.2, Custom 4.1. In other words if your baseband is 4.26.08, 5.11.07, 5.12.01, 5.13.04, 01.59.00 then you can successfully follow this video directions. And if your baseband is 5.14.02 or 5.15.04 then you will need to follow the video given at the end of this written description. All this will be an Untether way of Jailbreak covering both new or old bootrom for your particular devices.

METHOD: First use Redsn0w 0.9.6b6 to put your iPhone in Pwned DFU mode so that it is able to accept Custom Firmware file. When iDevice in Pwned DFU mode then simply open iTunes and hit Shift + Restore (Windows) or Option key + Restore (MAC) and load in Custom 4.2.1. Sit back and relax till updating/restoring process is done. When it is all ready then simply install "Ultrasn0w" from Cydia. You will be fully Unlocked and Jailbroken on 4.2.1 Firmware.

Download Redsn0w for WINDOWS: mega.co.nz/#!Qw8QXCBA!RSIEDz-XHViVsPPmmkYqXAODM…

Download Redsn0w for MAC: uploading.com/files/fb6da8c3/redsn0w_mac_0.9.6r…

IF above Redsn0w gives you issues while running, then run these versions of Redsn0w
Mac: uploading.com/files/b2b43924/redsn0w_mac_0.9.6b…
Windows: uploading.com/files/m8cm96de/redsn0w_win_0.9.6b…

Download Official iOS 4.2.1 firmwares iclarified.com/750 (Browse in Redsn0w 0.9.6b6)

Below are the CUSTOM 4.2.1 Firmwares: (Browse in iTunes)

Custom 4.2.1 Firmware for iPhone 3g - mega.co.nz/#!Ql1WHJCJ!WQvhJhahSrt1XGo7a0H2ElURd…
Custom 4.2.1 Firmware for iPhone 3gS- 4shared.com/file/QsNMrLje/iphone21_421_8c148a_c…?
Custom 4.2.1 Firmware for iPhone 4 - 4shared.com/file/1qBVt3RK/iphone31_421_8c148_cu…?

Users with iPhone 3g or 3gS and have updated to Official 4.2.1 firmware directly through iTunes need to follow this video to Unlock their devices youtube.com/watch?v=yHCmV1GO5xI

[Here is a complete list of errors while Upgrading/Downgrading an iPhone/iPod Touch or iPad Firmware bit.ly/hUCZHi]

NOTE: (ONLY iPhone 4 Users): This video is for unlockers. The custom firmware used here are 'hacktivated' and you will NOT get a service if you use these with official sim cards on your iPhone 4. You will have to use Pwnagetool (MAC) or Snowbreeze (WINDOWS) to make your own custom 4.3.1 firmware and make sure to Uncheck 'Activate iPhone' option when you make a custom firmware using pwnagetool or snowbreeze. Then upload that on your iPhone. You will get your reception back on iPhone 4.

All Credits go to:
MuscleNerd
iH8sn0w
iPod2g

Happy Jailbreaking !!

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