iOS 4.2.1 SHSH Blobs Lost, Can I Still Jailbreak?

Hello Jonathan, of course, you can still jailbreak your iPhone 4 even without SHSH Blobs. In fact, you don’t need SHSH Blobs unless you want to downgrade the firmware version of your device to older version. For instance, in your care, let’s say that you have upgraded to iOS 4.3.3 and after days of using your iPhone 4 to iOS 4.3.3 you find it a bit laggy, has a battery issue, etc. Then if you want to downgrade, you will need to have saved iOS 4.2.1 SHSH blobs to downgrade your firmware to iOS 4.2.1. SHSH Blobs is unique for every device and hence you cannot use the SHSH blobs of someone else’s device in order to downgrade the firmware version of your iPhone 4.

Regarding about jailbreak tools, this actually depends on your needs and what kind of machine / operating system you are using. If you want to jailbreak your iPhone in order to unlock it using Ultrasn0w and you are on Mac OS X, then you should use PwnageTool to jailbreak your iPhone.  If you are a Windows users who want to jailbreak and unlock, then you should jailbreak your iPhone 4 using Sn0wbreeze. If you don’t care about unlocking your iPhone, then the best and less complicated jailbreak tool to use is Redsn0w, which is available for both Mac OS X and Windows. You can follow our step by step guide on how to jailbreak iOS 4.3.3 using PwnageTool 4.3.3.1, Sn0wbreeze 2.7.1, and Redsn0w 0.9.6rc16.