Apple has releases the iOS 5.0.1 for public iOS user’s devices with high-security patches on the core of iOS, which prevents the users from jailbreaking the device, as well as from downgrading the devices from the newer version, even if you have saved the SHSH blobs. If you don’t know, the jailbreak hacker MuscleNerd already warns the users on his twitter account to stay away from iOS 5 updates, because Apple baked iOS 5 with new core utilities, which could not allow users to downgrade their device to older versions with saved SHSH blobs.
The iPhone Dev Team once again reminds us not to update your devices to iOS 5.0.1 because currently there is no method available to downgrade your device to older iOS 5 version, and the jailbreak hackers already on the last stage to release the untethered jailbreak. So if you are one of those who rely on the iPhone Unlock, you must have to prevent the iOS update.
MuscleNerd of the iPhone Dev Team says saved SHSH blobs of iOS 5 is not sufficient to downgrade the device from iOS 5.x.x to stock iOS 5.0. The dev team has announced to stay away from the new iOS 5.0.1 update until they discover a method of downgrading device for iOS 5.x.x to iOS 5.