Update iPhone 4 on iOS 4.1 to Retain Original Baseband 1.59.00 Unlock

As the baseband has been updated to 2.10.4 in the iOS 4.1 firmware, carrier unlock tool Ultrasn0w 1.1-1 won’t be able to unlock your iPhone 4 or iPod Touch 4G. Even after downgrading iPhone firmware back to iOS 4.0.x, the baseband does not change. You may follow simple steps listed below to update iPhone 4 to iOS 4.1 without upgrading 1.59.00 Baseband to 2.10.4.

Notcom has now updated TinyUmbrella which provides baseband protection for your iPhone 4 or iPod Touch 4G riding on iOS 4.1. Previously, while upgrading to latest firmware on new baseband, it wasn’t possible to downgrade the baseband regardless of firmware downgrade. But now, you can downgrade baseband as well, till Apple signs iOS 4.0.2 firmware. For example, if you update your iPhone 4 to iOS 4.1, your baseband will be updated to 2.10.4 and when you downgrade it to iOS 4.0.2 your baseband will be downgraded to 1.59.00 which wasn’t possible before.

NOTE: The following guide will upgrade your iPhone 4 to iOS 4.1 while preserving your current baseband. If you are on iOS 4.0.1, you will lose your jailbreak and unlock. However, if you have already saved your SHSH Blobs for 4.0.1 or earlier, you can retain jailbreak and carrier unlock on your iPhone 4. If you want to play with iOS 4.1 and want to get your hands dirty, follow the process below in upgrading your iPhone to iOS 4.1 while retaining original baseband

How to Update iPhone 4 on iOS 4.1 Without Upgrading 1.59.00 Baseband to 2.10.4

Step 1: Download latest TinyUmbrella 4.1.3

Step 2: Carry out the steps below to flawlessly downgrade baseband.

• Close TinyUmbrella (if open)
• Close iTunes (if open)
• Remove ALL lines in your hosts file that contain gs.apple.com
• Windows: Start -> cmd -> ipconfig /flushdns
• Mac: Terminal -> dscacheutil -flushcache

Step 3: Start TinyUmbrella 4.1.3

Step 4: Click Save My SHSH to save your 4.0.1 or 4.0.2 SHSH blob

Step 5: Start the TTS Server

Step 6: In order to fix 3002 errors, if any, check the Advanced Options. In the Device/Version box, select iPhone 4.1 (8B117) and Click Save My SHSH again to save a 4.1 SHSH blob. Make sure iTunes is still closed

Step 7: Start iTunes and hit the restore button to restore to iOS 4.1.

Step 8: A screen will come prompting you to select iOS 4.1 Software update. Accept the iOS 4.1 Update and select Next to continue.

Step 9: After the update process is completed, iTunes might show the following error messages: “The iPhone could not be restored. An unknown error occurred (10044).” and “iTunes has detected an iPhone in recovery mode. You must restore this iPhone before it can be used with iTunes.” Press “OK” to continue.

Step 10: Return to TinyUmbrella and select “kick device out of recovery” to restart your device normally.

Voila! Your iPhone 4 is now on iOS 4.1 with the older 1.59.00 baseband !

On iOS 4.1, you will surely lose your jailbreak on your iPhone and iPod Touch, and being latest firmware you might face incompatibility issues with your favorite iPhone apps forcing you to return to old iOS 4.0.1 firmware. If for any reason, you upgraded it to iOS 4.1 and would go back to 4.0.1 or iOS 4.0.2, then follow the steps (posted here). Once Downgraded, you can jailbreak and carrier unlock (all basebands) you iPhone 4 and iPod Touch 4G using following guides:

• Jailbreak iOS 4.0.1 iPhone 3G with Redsn0w 0.9.5
• Jailbreak iPod Touch on iOS 4.0 / 4.0.1 using JailbreakMe
• Jailbreak iOS 4.0.2 iPhone 3G, iPod Touch 2G with Redsn0w 0.9.5
• Unlock iPhone 4 iOS 4.0.1 with Ultrasn0w