These days, in order to downgrade an iOS device to a previous version of iOS, you need to have an old SHSH blob of that version, and the only way to do that is to back it up ahead of time, that is, when Apple is still signing the firmware. iSHSHit is a tool that backs up the firmware's blob for later use right on the device itself. The said app has now been updated to work with iOS 4.3.4 and 4.2.9 (for CDMA iPhones), which were both released to the public last week.
According to i0n1c, a well-known member of the iOS jailbreaking community, users should not expect to see an untethered jailbreak for the just-released iOS 4.3.4 anytime soon.
With iOS 4.3.4 just released, rendering the also just-released super-simple JailbreakMe useless, some might be wondering how to jailbreak the new release of iOS. Well the iPhone Dev Team has just pushed a small update to Redsn0w to make it compatible with the just released iOS 4.2.4 firmware. This new version of Redsn0w can tether jailbreak most iOS devices on iOS 4.3.4, namely iPhone 4, 3GS, and iPod touch 4G/3G. The only device that's not supported at the moment is the iPad 2. The process should only take a few minutes to get Cydia up and running on your device.
Earlier today, Apple released iOS 4.3.4 to close the PDF jailbreak hole which was exposed by Comex’s JailbreakMe 3.0. We have already warned you NOT to update to 4.3.4 if you want to keep your untethered jailbreak. If you updated by mistake, you can downgrade back to 4.3.3 and enjoy full untethered jailbreak as long as you have saved SHSH blobs for the firmware you are downgrading on.
Apple has just pushed out iOS 4.3.4 for the iPhone, iPad and the iPod touch. And thankfully, we have cooked custom PwnageTool bundles which allows you to jailbreak any device (except for iPad 2) running iOS 4.3.4, and at the same time preserve your baseband for an Ultrasn0w unlock later on.
As we've speculated over the last few days, iOS 4.3.4 made its debut on iTunes. The new release, without clear release notes, addresses the PDF exploit in Mobile Safari used by JailbreakMe.
It has now been confirmed that Apple is planning to release iOS 4.3.4 to fix a PDF Exploit that allowed JailbreakMe 3.0 to be applied. This vulnerability in Mobile Safari requires users to open a malicious PDF file before having the device taken over and ultimately jailbroken in JailbreakMe 3.0’s case.