You all must be aware of the Tool called Tiny Umbrella. Yes the same tool used to save your SHSH Blobs and helps you in restoring and fixing the recovery boot loop. Today Tiny Umbrella was updated to the new version of 5.00.7 with a new feature for iPhone 4 users only.

When ever you needed to update the iOS your Baseband was also updated. That was the thing which you don’t wanted to. Because you get locked on the new Baseband and lost the Unlock and have to wait for ages for the Unlock to come, which is not a good option. So Notcom the Developer of Tiny Umbrella updated its tool with a new option of Baseband update. Now it is up to you whether you want to update the baseband or not.

This is what he said on his blog:

I’ll probably regret this but this newest version of TU (5.00.07) will allow you to choose whether or not to update your iPhone 4’s baseband. This new feature comes with a catch:

  1. First, the version you WANT to restore to and the version Apple is currently signing must BOTH have the same baseband. This is important or else the baseband update will not work and you will get a 10xx error and need to use fixrecovery. (Works for iPhone 4 – will not work for iPad 2)
  2. Second, you need to realize that checking the box WILL UPDATE YOUR BASEBAND.
  3. Third, I’m working on a simple tool that will allow you to create a pseudo-custom firmware mixing a new baseband with an older iOS version (one that is jailbreakable for example). This feature exists in the TinyUmbrella rewrite but does not yet exist in the older codebase. SORRY! I’m working on it!

I do not save your ‘UPDATE iPHONE 4 BASEBAND’ setting. If you wish to restore while updating/restoring your iPhone 4 baseband you must check that box every single time you run TinyUmbrella. It is just safer that way.

Also, iPad 2 users can still restore to 4.3.3 if they have their 4.3.3 SHSH. Just ‘Start TSS Server’ and then start up iTunes and restore your 4.3.3 ipsw. TinyUmbrella should help you restore without a 10xx error.
Enjoy!
This works like this. Like iOS 5 is around the corner and you are dieing to update to iOS 5 because of it’s cool features, but on the other hand you cannot because it got a new Baseband and it will refrain your Unlock. So you are stuck for the time being.
Now with this tool all you have to do is that keep in mind the first point that the firmware you are trying to restore must have the same baseband and that firmware should be signing by Apple have the same baseband, then only the update for baseband will work other wise it won’t.
To clarify it more lets assume we got iOS 5 and the baseband is 4.11.04. You want to restore to iOS 5 and you got the same baseband which is in iOS 5, which is 4.11.04. Then it will work flawlessly.
On the other hands you are willing to restore from iOS 5 to iOS 4.3.4 which is not signed by Apple and doesn’t have the same baseband. It has the old baseband 4.10.04. So you will end up with Error 1oxx and you can fix it with Fix recovery. This is what i understood. If you understood better than me and want to contribute, so most welcome and feel free to share with us and others.
Download Tiny Umbrella for MAC OS X and Windows from here.