We’ve already reported that Apple has released iOS 4.3.4 for iPhone, iPad and iPod touch. Following the upgrade, Notcom has upgraded the TinyUmbrella SHSH blobs saving tool to v5.00.05 which can now save SHSH blobs of supported iOS devices running iOS 4.3.4.
SHSH blobs are also saved by Cydia, but it is advisable to use TinyUmbrella on Windows or Mac to save SHSH blobs because of the fact that the process is considerably faster.
What is TinyUmbrella? Well basically, it has two functions. TinyUmbrella requests SHSH signatures for firmware restores and also plays back those signatures enabling iTunes to continue the firmware restore on your iOS device.
The primarily reason due to which Apple has released iOS 4.3.4 is that it wanted to patch the PDF exploit used by JailbreakMe 3.0 to easily jailbreak iPhone 3GS, iPhone 4, iPad 1G, iPad 2 and the iPod touch 3G/4G. Not only was jailbreaking through JailbreakMe 3.0 exceptionally fast, it also allowed jailbreaking the iPad 2 on iOS 4.3.3, which was the only method made public. There’s no other way to jailbreak iPad 2 right now.
We must first understand how JailbreakMe 3.0 worked. It used a vulnerability present in iOS Safari, and by gaining root access through it, installed Cydia on your device in the most convenient manner possible. As previously mentioned, despite various claims made by other dev teams about the progress of iPad 2 jailbreak release, Comex was the only one to release his iPad 2 jailbreak to the public. So when that happened, it was speculated that Apple would release a new firmware upgrade to patch this vulnerability. Any hacker wishing to gain root access to your device could use this vulnerability and naturally, Apple had to patch that, not undermining the fact that it would eliminate JailbreakMe 3.0 as well. Comex himself released PDF Patcher 2, which patched this vulnerability and retained the jailbreak, however, iOS 4.3.4 will make you lose your jailbreak.
Its important that you save iOS 4.3.4 SHSH blobs right now. Apple is also currently signing iOS 4.3.3 as well, so you can save those blobs as well. Once you have them, its going to be easy to downgrade back to iOS 4.3.3 and jailbreak iPad 2 using JailbreakMe 3.0. Keep your blobs safe, and its always wise to email a copy to yourself, for safekeeping.