Semaphore aka notcom has just updated its flagship TinyUmbrella utility to version v6.00.00, extending its support to Apple TV on iOS 5.0.2 and iOS 6.0 support (including betas) to all iOS devices. All users who seeks jailbreak in future must download the newest TinyUmbrella and save their SHSH blobs right away. If you accidently updated your device to newest firmware, these backed up SHSH blobs will come useful in event of downgrading the firmware.
Without these saved SHSH blobs, you will not be able to downgrade to old ipsw to re-jailbreak your iOS device (if exists). So what are you waiting for? Hit up TinyUmbrella 6.00.00 download link.
Steps to save iOS 6.0 SHSH Blobs files on Mac or Windows
Step 1 : Download TinyUmbrella v6.00.00b from here to your Desktop.
Step 2 : Double click .dmg file to mount it and drag the Umbrella app from the mounted dmg into your Applications folder. Double click the Umbrella app to launch it.
Step 3 : Enter administrative username and password. Utility will then detect the type of device and its firmware.
Step 4 : Click the Advanced Tab. Since Cydia is no longer able to proxy SHSH request, uncheck Set Hosts to Cydia on Exit and Request SHSH from Cydia.
Step 5 : To obtain SHSH BLOBS for the latest iOS 6.0 firmware version, Press the Save My SHSH button.
You will notice a new entry in the Saved SHSHs for iPhone list confirming that you have successfully taken backup of your SHSH blobs. If the file that gets saved is anywhere from 60-65k bytes then the file should be just fine.
If you have trouble saving your SHSH file for iOS 6.0 betas using TinyUmbrella, just go to advanced settings of the TinyUmbrella and Uncheck the Request SHSH from Cydia option (as shown in screenshot below). Then tap on Save SHSH.