Update to iOS 5.0.1 After iPhone 4 Baseband Downgraded to 4.10.01 via Chips Replacement

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Got your baseband downgraded from 4.11.08 to 4.10.01 via baseband chips replacement but still on iOS 4.x.x? Follow these simple instructions on how to update to iOS 5.0.1 without losing your unlock.

Please do note this tutorial is written for our customers who have used our iPhone 4 baseband downgrade service. Currently, there’s no way to downgrade your baseband except by replacing the Infineon x618 chip and Intel/Numonyx NOR chip on the logic board.

There’s a chance that you’re still on iOS 4.x.x because you managed to save your SHSH and downgraded your iOS and hoping that your baseband would be downgraded as well (which won’t happen anymore since Apple had stopped signing iOS 4.3.5).

Editor's note: learn more by reading our ebook on starting your own iPhone repair & unlock business

However, now you’re a bit paranoid to update to iOS 5.0.1 because of baseband 4.11.08. Don’t worry – you can still enjoy the benefits of iOS 5 while preserving your baseband using custom firmware.

Before you begin:

  • Backup, backup and always backup!
  • Download and install iTunes 10.5.x
  • Have a clear and relaxed mind

To accomplish this, there are 2 options:

  • Adventurous Mode: Build your own custom firmware, restore and then unlock with Gevey Turbo SIM
  • Lazy Mode: Download the custom firmware (pre-built by us), restore and then unlock with Gevey Turbo SIM

ADVENTUROUS MODE

1. Download iOS 5.0.1 original firmware from here.

2. Download the latest sn0wbreeze (version 2.9.1, Windows only) from ih8sn0w.com.

3. Launch sn0wbreeze and click on the blue arrow at the bottom right corner.

4. Browse for the firmware you just downloaded in step (1). Click next.

5. IPSW is verified. Let’s select Expert Mode (for the fun of it).

6. Click General and hit next. It’s very likely that you don’t have the official SIM card so check ‘Activate The iPhone [Hacktivate]. If you’re familiar with installing custom apps or changing boot logo, then go ahead and customize them yourself.

7. Click Build IPSW then wait until the custom firmware is ready. Once done, you should find it on your desktop with the file name:

sn0wbreeze_iPhone_4-GSM-5.0.1-9A405.ipsw

8. Before restoring, you need to ‘pawn’ DFU your iPhone to allow it to accept custom firmware. Otherwise, you will get error 1600. Sn0wbreeze will guide you how to pawn DFU your iPhone using iREB.

9. Launch iTunes 10.5, then while pressing shift on your keyboard, click on Restore. Point it to the custom firmware on your desktop. Wait until the restore is complete. Your iPhone will boot up and you’re ready to unlock it with your Gevey Turbo SIM. If you have Gevey Ultra, then install the latest patch from FuriousMod.

Note: The unlocking step is slightly different as there’s no one signal bar after hitting ACCEPT, it shows NO SERVICE but you can still dial 112.

LAZY MODE (also suitable for Mac users)

1. Download custom iOS 5.0.1 from here (filefactory changed their file download policy after megaupload.com was shut down).

2. Use the latest redsn0w (Windows or Mac version available) or iREB to pawn DFU your iPhone.

3. Launch iTunes 10.5, then while pressing shift on your keyboard, click on Restore. Point it to the custom firmware on your desktop. Wait until the restore is complete. Your iPhone will boot up and you’re ready to unlock it with your Gevey Turbo SIM. If you have Gevey Ultra, then install the latest patch from FuriousMod.

Note: The unlocking step is slightly different as there’s no one signal bar after hitting ACCEPT, it shows NO SERVICE but you can still dial 112.

Common Issue:

iPhone stuck on Apple logo during reboot – Hard reset and then try to turn it on again. If that doesn’t work, build a ‘Baseband Preservation Mode’ custom firmware in sn0wbreeze, restore your iPhone and then jailbreak it with the latest redsn0w to hacktivate it. This will also give you untethered jailbreak.

That’s it! Remember that you must always use this method to update to any new iOS version to preserve your baseband. This tutorial is valid for as long as the tools are readily available or supported.

Share this and be awesome!

Comments & Discussion

    • Technically speaking, you're not changing the IMEI, you're changing the chips to downgrade the baseband to 4.10.01. Inadvertently this changes the IMEI since it's stored inside the same chips.

  1. We get refurbished(second hand) in awesome condition phone for almost 250$ in India…then why Would anybody want to spent 168$ ….on a chipboard whIch may be risky as well since the iPhone 4G 4.11.08 needs to be opened…I would suggest Wait and get an almOst free solution

  2. hi after i tried to update my ios to 5.0.1 i cannot sync my apps to my iphone..it always say 'failed to install' something like that..what should i do? is there something wrong with my iphone.. i followed everything..plz help..

  3. Does this process still (3-May-2012) apply?

    I have an iPhone 4 with iOS 5.0 (not 4.0) with baseband preserved to 4.10.01. Can I still upgrade my iPhone to iOS 5.0.1 using the above process?

    If the answer is no, please still leave a response. Thank you.

    • You need to have the SHSH for 5.0.1, you can still update to iOS 5.1 preserving your baseband, activation will be via official SIM or jailbreak (tethered on 5.1)

  4. i tried it the same way u said but i am getting an error 1602 and my baseband is still on 4.12.01 pls what can i do i cant use my iphone now

  5. i tried this method but my iphone would not restore and i am getting the error message 1602 what can i do pls i really need your help

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