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Thread: How do I update to 4.2.1 while not losing files and keeping my baseband?

  1. #1

    I have not found any post where it contains information about the tittle.

    My iPhone Specs:

    iPhone 3G
    iOS 3.1.2 Jailbroken with Blackra1n
    Baseband 5.11
    Using another carrier from a different country (i'm in the US)

    How do you update iOS 3.1.2 to 4.2.1 jailbroken while keeping my baseband?

    Will I be able to have an unlock?

    Will I lose any of my data? (EVERYTHING, Contacts, Apps) (I don't really care about any jailbroken data)

    Thank You!

    Last edited by trypwned; 2011-07-09 at 10:33 PM.

  2. #2
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    1) Open iTunes with device plugged in, right-click in left panel your device, select "transfer purchases" then do it again and select to create a backup.
    2) To back up jailbreak data, purchase Pkgbackup (a free alternative is aptbackup, however I would recommend pkgbackup as the latter is not reliable. Use it at your own risk, expect not to gain anything back bc this can happen if you choose not to purchase pkgbackup)
    3) To ensure your other data is properly backed up, just in case something goes wrong with an iTunes created backup, go to the info tab in iTunes and select a third-party option to put your contacts into. Also go into your My Computer and select your device, copy all of those photos/videos to your computer.
    4) You may also consider if you know how to SSH into your device to copy any themes or other items you find important and store them into your computer.
    5) When you're finished backing up your device, you will want to create a custom firmware with sn0wbreeze. Be sure to find the version that is for 4.2.1. While you're at it, download a stock 4.2.1 ipsw from You will be using 4.2.1 because that is the highest fw version the iPhone 3G is capable of reaching. Be aware, 4.2.1 will run slower than 3.1.x.
    6) Using sn0wbreeze to create a custom 4.2.1 firmware will preserve your baseband and allow you to unlock the device on 4.2.1. When creating the firmware, if you do not have an official SIM to activate with, be sure to create an activated fw. To do so, when you open Sn0Wbreeze, simply enter Expert mode and in the General menu you can select the box for "activate" then build your firmware. If you DO have a SIM to activate officially with, avoid creating an activated firmware. Be sure to do the above steps except ensure the box to "activate" is *not* checkmarked.
    7) When you've finished creating your custom firmware (or while you are doing that) download Redsn0w (the latest version will do). Once you've got your custom 4.2.1 firmware ready, be sure it is on your Desktop for easy access or somewhere you can find easily. Do not mix it in the same place with the stock firmware or you might accidentally select it and ruin your unlock.
    8) With redsn0w first, browse to the *stock* 4.2.1 and continue, then select *ONLY* the dfu mode option. Follow the instructions.
    9) When your phone is in pwned DFU mode, open iTunes. Hold shift and click "restore" and select your custom firmware.
    10) When iTunes finishes, if you restored with an unactivated custom firmware, you may open iTunes and activate the phone now with the SIM. If you used an activated version, you should already be able to access your springboard.
    11) Go to Cydia and install Ultrasn0w to unlock.
    12) In iTunes, when it prompts select to restore from backup and select the most recent backup you have. Go to Cydia and re-install pkgbackup (if you used aptbackup, reinstall that) and run the program to restore your jb data.
    13) If you notice push failure and perhaps abnormal battery drain due to restoring to an activated version of the custom fw, simply install SAM from Cydia. To use SAM, google a guide on how to use it. This will "unhacktivate" the device so that the problems will be gone.

    If you have any further questions, feel free to ask.

    Edit: I forgot to mention, because 4.2.1 runs a bit slower on an iPhone 3G, consider not having the typical iOS 4 features such as Wallpaper and Multitasking. This will greatly improve the speed on the device. When creating a custom firmware in Sn0wbreeze, under General (I think) be sure that those features are not enabled.

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