So you installed the latest version, iOS 4.3.4 on your iPad / iPad 2 that has patched the PDF exploit devised by Comex and everything is smooth. However, you just realize that the jailbreakme jailbreak no longer works with it and now you want to rollback to jailbreakable iOS 4.3.3. Here is a step by step guide on how to do it:
Before you begin, you must understand that the SHSH blobs must be present at Cydia. They can be of any version – iOS 4.3.3, 4.3.2 or 4.2.1. First, you will need to download iOS 4.3.3 for iPad. After that, you will need to put it in DFU mode. For that, connect you iPad to your computer and turn it off. Hold the power button for 1 second and then while holding it, press the home button as well. Then, after few seconds, while holding the home button, release the power button. iTunes should be able to recognize your iPad. Now we are going to fool Apple’s servers as they don’t want you to downgrade (and thus perform iPad 4.3.3 untethered jailbreak).
Now, if you are windows user, go to "C:WindowsSystem32driversetc" and find the file called "hosts". Mac users can access this file by going to ‘/etc’ folder. Open this file (in notepad (windows) / textedit(mac)) and at the end add this line "18.104.22.168 gs.apple.com". Windows 7/Vista users should open the above file with administrator privileges. If you are a Mac user and is having trouble in saving the changes (permission error), copy it to desktop; make the changes and copy it back to its original location.
Now, launch iTunes; find your device in the left sidebar; press and hold the shift key (windows) / alt key (Mac) and press "restore" button. Browse for the iOS 4.3.3 IPSW and flash it to your iPad. Now, you will have to get it out of recovery mode. Download Tinyumbrella (windows version, mac version); start it and click on the button that says ‘exit recovery’. Good job – you have done it.
Note – iPad 2 3G 4.3.4 cannot do use this guide. They simply cannot downgrade.