Now that Redsn0w 0.9.6rc9  finally provides the long awaited iOS 4.3.1 untethered jailbreak, many iPhone 4 owners with unlocked iPhones’ have been advised to hold off upgrading to 4.3.1 as you will lose the ability to unlock, since the newer firmware will update your baseband.

Furthermore, as we’ve mentioned earlier this morning, the new iOS 4.3.1 firmware currently is incompatible with the Dev Team’s ultrasn0w unlock tool. It is recommended that you wait for the Dev Team to update this tool before upgrading and jailbreaking.

But for those anxious to update to the new iOS 4.3.1 firmware and still preserve their iPhone 4 1.59.00 baseband so they can be guaranteed an unlock when the Dev Team updates their ultrasn0w tool, follow our tutorial below. 
In this tutorial, we will show you how to upgrade your iPhone 4 to iOS 4.3.1, without upgrading its baseband, using TinyUmbrella for Windows.

For those using a Mac, follow our tutorial here to preserve your baseband using Pwnage Tool.

Windows users follow our guide below to update your iPhone 4 to iOS 4.3.1 and preserve your 1.59.00 baseband.

NOTE: This will only work for the iPhone 4.

If you are unsure as to what baseband your iPhone 4 is on, launch Settings > General > About  > Modem Firmware.

Step 1: Download TinyUmbrella from here
Step 2: Connect your iPhone 4 & Launch TinyUmbrella

Step 3: Click On the “Save SHSH” button

Step 4: Now, Click on start the “TSS Server” button

Step 5: While the TSS server is running, Launch iTunes

Step 6: Now, Click on Restore in iTunes (Don’t Click on Update)

Step 7: During the Restore Process, iTunes will give you Error 1013. Don’t panic, this is good. This error means your baseband has been preserved. Exit out of iTunes.

Step 8: Place your iPhone into DFU mode by holding down both the Power and Home buttons for ten seconds, then release the Power button and continue holding the Home button for another 5 seconds.

Step 9: Fix Recovery in TinyUmbrella is currently not working. Download this standalone .exe file to fix recovery on 4.3.1. Extract the file and double click on fixrecovery43.exe. A command prompt will open, and the program will go through the process. During this time, you will notice scrolling text on your iPhone 4.

Step 10: Your iPhone will now be on 4.3.1 with the 1.59.00 baseband! To jailbreak your iPhone 4 on iOS 4.3.1, follow our tutorial here!


Update: The iPhone Dev Team has released an updated version of the ultrasn0w unlock tool that is compatible with iOS 4.3.1.

Note: This will only unlock iPhone 4 on 1.59.00 baseband. Follow the tutorial here to unlock your iPhone 4 on iOS 4.3.1.

  • Burge

    You have got to love jailbreak day 
    It’s all my phone crashes at *********
    Or it’s not working 
    In the end everyone gets there ..just try ..try and try again …

  • Sotoy

    If you upgrade to 4.3.1 while preserve your bb on 01.59 or 02.10, you will get ONE bar ONLY no matter where you are, guaranteed … as shown on picture… LOL 🙂

    • lawrence091

      Do we know why this is happening? This is happening with mine also.

    • Jahaziel

      So if I update to 4.3.1 and preserve 1.59.00 and DONT need unlock will it affect signal strength??

      • lawrence

        it’s just showing one bar no matter what, i don’t think it’s actually affecting signal strength…it could be at full strength but still show one little bar! Ugh!

    • Gumba


      I’m getting that too… on I have 3G download speeds of 7mbps, while on 1 or 0 bars!

      I do miss being able to see the strength.

      I assume its an incompatibility between baseban 1.59 and iOS4.3.1

      I was running 4.0.1 and 1.59 before

  • DebTym

    kind a complicated i even the updated ultrasnow is released..we need to follow this procedures? esp. i’m a windows user.

    • Kickstar13

      Yes. If you want to update to iOS 4.3.1 and unlock, you need to preserve 1.59.00 baseband.

      • DebTym

        thanks, i’ll just bookmark this and wait until the updated ultrasnow is release.

  • rlamba

    Can you upgrade to 4.3.1 on 6.15.0 bb?

    Is there anything to downgrade 6.15.0 bb?

    Many thanks for any help.

    • Burge

      Yes you can upgrade and no your baseband will not downgrade ever..

    • Reytube

      U need a custom firmware

  • Ifti

    Are they any activation issues ? The last jail break didn’t activate the phone hence it required original sim to activate the phone

  • Joseph


    I have a question, does anyone know if iOs 4.2.1 works with a 4.10.01 baseband?? The reason I’m asking is because I tried to downgrade it to 4.2.1 but the carrier SIM is not picking up on my phone. (It says no service) I’m guessing that there might be some problems with the baseband not compatible with the firmware. Are any of you having this problem? Or is it just a problem with my phone?

    I appreciate it if anyone here can help me out, THANKS!!


    • Kickstar13

      You cannot unlock that baseband with ultrasn0w. Only iPhone 4 baseband 1.59.00 can be unlocked using ultrasn0w.

  • thatguy

    This is one way to do it, but PwnageTool works for all phones for preserving the baseband, not just the iPhone 4.

  • Konkuku

    to Joseph
    My phone also IOS 4.2.1 works with 4.10.01 bb
    can I unlock 4.10.01 bb later?

    • Kickstar13

      No, currently only iPhone 4 baseband 1.59.00 can be unlocked.

  • Bytenapple

    I wonder if the Dev Team would be able to reaease and unlock for newer basebands of we all donated a little something to their cause. It’s probably more likely than not. Just think about it. The more cash flow they have, the more time they will be able to spend developing unlock and jailbreak solutions for us. This would allow them to spend less time doing their day jobs and decrease our wait time for their solutions to our idevice’s needs. We don’t have to give much but just think how far $5 would go if we all pitched in. That’s the price of an app. Then, maybe the tables will turn on the whole cat and mouse game, and it will be more like a cat vs cat game. I for one would love to see what they would be able to accomplish with all of the resources they need available to them.

    • Kickstar13

      They don’t accept donations. They’ve stopped accepting donations a while ago.

  • DebTym

    i have one more question..please iphone 4 is currently on 4.2.1 so if i follow that process will it also update my ip4 to 4.3.1 or i have to update first to 4.3.1 then follow that?

  • Ifti

    Im sooo confused
    If i update using this method wont redsnow jailbreak update my baseband anyway ?
    The redsnow tutorial doesnt say anything about baseband

    • Kickstar13

      After you follow the tutorial in the article above you will preserve your iPhone 4 baseband 1.59.00. When you run the redsn0w jailbreak, it does not touch your baseband. It simply injects a line of code to give your device root access.

  • ifti

    hmm thanks for the reply

    but the jailbreak 4.3,1 with rensnow tutorial says

    “Unlike PwnageTool, RedSn0w updates your baseband, so this is probably your preferred jailbreak method if you don’t rely on an unlock…. ,”

    so this is why i needed confiirmation lol please can someone else confirm this also
    two sources are better than one!

    • lawrence

      I didn’t need to run tss server from tiny umbrella. I just did restore 4.3.1, kick it out of recovery loop and ran JB, preserved BB..

  • daz

    i got eror 1611 ,i try this step but nothing happening

  • arfaei

    My iphone 4 is on 4.1 with 1.59 baseband.should i use the new sn0breeze or should i do it this way?
    the baseband preserve mode on sn0breeze 2.5.1 only updates ur phone to 4.3.1 and does not jailbreak it but it says all the other modes still presereve baseband.but I dont know if I should use the expert or simple mode becuz im afraid it might update the baseband.

    • Kickstar13

      Both methods will work perfectly fine. The TinyUmbrella method is a little faster, and personally, I prefer it.

  • John

    Hey guys, quick question. I have an Iphone 4 jailbroken and Unlocked on 4.2.1 bb 01.59.00 and should i update to 4.3.1 with TinyUmbrella and preserve my baseband to 01.59.00( i have my SHSH blobs saved) and then jailbreak it with RedSn0w? My question is that when i update to 4.3.1 and want to jailbreak with Redsnow, will it update my baseband as well as said on tutorial? Please Help. Thanks a lot