How to Downgrade iPhone 4 iOS 5.1 Baseband 4.12.01 to 4.11.08 for Possible (Future) Unlocking

UPDATE #1: Ooops… Apple is fast this time. iOS 5.0.1 is no longer being signed. Baseband downgrade to 4.11.08 is no longer possible.
Did you just update your iPhone 4 to iOS 5.1 and found out that you now have baseband 4.12.01 that can’t be unlocked? See below on how to downgrade your baseband for possible unlocking in the future.

First things first:

• This tutorial will be valid for as long as Apple is still signing iOS 5.0.1. Once Apple stops signing iOS 5.0.1, you can no longer downgrade your baseband to 4.11.08. You will get error 3194 on iTunes.
• Baseband 4.11.08 cannot be unlocked at this point but downgrading your baseband to this version increases your chances of unlocking your iPhone 4.
• You must do it now because Apple will stop signing iOS 5.0.1 anytime soon. It was still being signed when I tested this about 15 hours ago. Apple stopped signing iOS 4.3.3 just about 5 days after iOS 5.0 was first released.

Here are the steps:
1. Download and install iTunes 10.5. You will need to remove iTunes 10.6 first.
2. Download iOS 5.0.1 firmware for iPhone 4 (IPSW) directly from Apple server.

3. Put your iPhone into DFU mode (search a tutorial on YouTube).
4. Connect to iTunes and it will say that your device is in recovery mode and needs to be restored.
5. Go ahead and click shift+restore (Windows) or option+restore (Mac). Select the IPSW you just downloaded in step 2.
6. iTunes will verify with Apple server and begins restoring your device. Once completed you will need an official SIM card to activate it. You can use other tools such as TinyUmbrella to confirm that you now have baseband 4.11.08. If you don’t have an official SIM card, don’t worry. As long as you’re on 5.0.1 you’re good.
7. Now download or build custom iOS 5.0.1 from here. (Note: files are hosted in FileFactory which may require premium membership, they changed their download policy after MegaUpload was shut down, sorry!)

8. Download latest redsn0w from the Dev Team’s website. Start redsn0w, go to Extras > Pwned DFU. This allows your iPhone to accept custom firmware. If you don’t do this, you will get error 1604, 1600 etc.

9. Connect your iPhone to your computer.
10. Click shift+restore (Windows) or option+restore (Mac) and select the custom iOS 5.0.1 IPSW you just built or downloaded.
This time your baseband will be preserved at 4.11.08 while running on iOS 5.0.1.
Again – do it now because once Apple stops signing iOS 5.0.1, you will be stuck on 4.12.01 with no unlocking in sight, possibly for a very long time. Also read here on why you shouldn’t update to iOS 5.1 yet.

Edit APN Settings on iPhone 4S If Cellular Data Network is Disabled (for Gevey Ultra S Users)

Can’t find your APN settings (Cellular Data Network editor) under Settings > General > Network? Install your carrier profile easily by following these steps.

This is a useful tip for iPhone 4S who needs to modify their APN settings especially when using Gevey Ultra S. An alternate method is to install jailbreak tweak such TetherMe. If your device is not jailbroken you can try the following.
1.On your iPhone 4S, connect to a WiFi network.
2. Launch the following website using Safari web browser.

http://www.unlockit.co.nz

3. Tap on Continue > Custom APN.
4. Choose Country and Carrier and then tap Create Profile. For this example I chose country as USA and carrier as T-Mobile.
5. Tap Install and confirm installation.
6. Reboot your iPhone and you’re done!
If you ever need to remove this profile, go to Settings > General > scroll down and you will see Profile: APN Carrier Settings. Tap on Remove. That’s it.

Thank you very much to our customer @Ahilan for this tip!

iOS 5.1 Updates iPhone 4 (GSM) Baseband to 4.12.01 and iPhone 4S to 2.0.10

After weeks of speculation, the iOS 5.1 was released yesterday with some updates to iPhone 4 and iPhone 4S basebands.

For unlockers like most of us here, we are more concern of the baseband than anything else. So, to summarize the baseband revision for iOS 5.1:

• iPhone 4S: 2.0.10
• iPhone 4 (GSM): 4.12.01
• iPhone 3GS: 5.16.05 (no change from iOS 5.0.1)

As far as we know, none of the basebands above can be unlocked.

The following are change logs/features of iOS 5.1 for your information:

• Enhanced Siri dictation support during text input “on supported devices” (iPhone 4S in 2011) (i.e. Turn on or off Bluetooth, take a picture etc.).
• Carrier updates (e.g. AT&T 11.1).
• AT&T indicator now says “4G” when applicable. (4S Only)
• Baseband updates.
• Battery life reportedly fixed.
• Fixes iPhone 4S support for Caller ID Name Display (on supported carriers – i.e. Rogers & Fido in Canada).
• Users can now enter any Apple ID to sign-up for an iCloud account. Previously, they had to use (or create a new) me.com email Apple ID.
• New Montesi Wallpaper
• Images can now be removed manually from the Photo Stream in iCloud. Any photos deleted are now also removed from other iOS devices connected to iCloud.
• Shake-to-shuffle bug fix, which caused the Music app to freeze.
• The Setup Assistant caused an “infinite setup loop” for some users. When the setup was completed, the iPhone would jump back to a “thank you” screen ad infinitum. Users had to reboot the device to restore functionality.
• SpringBoard bug fix, the home screen for the iPhone would sometimes fall into a state when double-clicking the home button would not display the Camera icon.
• Turn on or off 3G toggle restored on iPhone 4S.
• Bluetooth bug fix; enabling Bluetooth and returning to home screen, the Bluetooth icon still remains in the status bar.
• Possible bug fixes on Wi-Fi signal strength on all devices.
• Safari, address bar added text (Go to this address).
• Improved Assistive Touch.
• Improved Location Services.
• License column added, under the About menu.
• Support for Siri in Japanese
• Possible fix to Outgoing Call No Audio (OCNA) issue.
• New Lockscreen camera button no longer have to double tap home button just swipe up to access the Camera app.
• Dictation on iPad

Meanwhile, as always, hackers should be back from their snooze mode by now to jailbreak this latest iOS release from Apple.

Thank you to those who have constantly emailed us asking how to unlock iPhone 4 on baseband 4.11.08 (and now 4.12.01) but there’s no method of unlocking it right now except by replacing the baseband and NOR chips. We are also exploring a new exciting method of making it “factory unlocked” by replacing one the chips inside. Stay tuned for this.

Once again, avoid updating to iOS 5.1 if you want to keep your untethered jailbreak or if you don’t wish to turn your iPhone into an iPod touch!

How to use TPSIM to unlock IPhone 4S?

NOTE: The default seeting work for US AT&T version,and the sim card inserted ATT version iphone4s together, it automatically unlock, signal stability.
If it is other carriers version iphone4s,please flowing the below three seting methods:

method1:The direct selection one of 9 preset operator's in the TPSIM.

the first, Any sim card ,turn on pin code.(you can use other mobilephone to do it)
Then, insert the sim card with tpsim together to iphone 4s.

For example: Softbank iPhone4 input 0002, Then show wrong,but card has been set for softbank version. And then take tpsim  and the sim card out, With real need to use sim card,
it can be automatically to unlock in Softbank iPhone4s
If use real need to use sim card to setting tpsim ,  after Setting ,pleae turn off pin.
Method2:  using activate sim card to automatic learning operators
The first, activate sim card's pin code turn on, and revised for 0000
Then inset sim card with tpsim into 4 s , input pin 0000 to unlock ,  successful  to set as activate sim card's operator
The last, use sim card and tpsim together into 4 s, boot can automatically to unlock

Method3: Through the manual input operator's imsi information to set the operators
If the user iphone4s version is no preset in tpsim card, and you have no activate the card, then can input operator's imsi to set the operators.
First find out imsi of mobile phone operators（you can Through the www.tpsim.com find Part of the operator's imsi or Their Google search can also)
Any a sim card with pin code on ,together inset phone4s, show needing input pin unlock ,input the part of  imsi,show wrong,tpsim had been set successful .For example US AT&T complete imsi is 0839011420123456. But only need to enter the back of the 08 figures for 39011420.
Tip from error, remove the card, completion set card has been working in custom to stick their sim card to insert mode can unlock.

The last, iphone4s will show needing input pin code to unlock,please input the code of your iphone4s’operator. Clik OK,iphone will show wrong code,don’t worry,tpsim had beed set to your operator.
Use your sim card (turn off pin) with the tpsim ,your iphone 4s ,will unlock automatically

Tpsim preset operators  pin code:

0001	KDDI AU	0002	SOFTBANK
0003	US ATT	0004	US Sprint
0005	Canada fido	0006	Canada rogers
0007	Aus  optus	0008	Uk 3
0009	Krea KT