Here is Quick Step by Step Guide to save SHSH Blobs using Tiny Umbrella for your Apple TV 2G on iOS 4.1
Step 1. Download the Latest Tiny Umbrella 4.1.5 or newer which supports the Apple TV from Tiny Umbrella Download:
Step 2. Now Connect your Apple TV to computer using Micro USB cable – However make sure Neither HDMI Nor Power Cord is connected to your Apple TV in order to enter the ‘Recovery Mode’ – iTunes Now Should recognize your Apple TV at this point.
Step 3. Now Launch the Tiny Umbrella which you downloaded in Step 1 and Make sure ‘Requested Version’ is Set to ‘Apple TV 4.1′ and ‘Request From’ is set to ‘Cydia’
Step 4. Now you would require to Enter ECID for your Apple TV Manually. Which you can find under System Profiler. Apple Logo -> About this Mac -> More Info (Under the USB Tab).
And Copy the ECID and paste that into Empty Field.
Step 5. Now Click on ‘Save my SHSH’ and It would start saving the SHSH Blobs for your Apple TV onto Cydia Server at the end of the Process you would be greeted with confirmation message. That’s it.
Now you can have Peace of mind while Apple Fixes the SHAtter exploit in next Hardware update, Since it’s low-level bootrom exploit so it won’t be possible for Apple to fix it by the OS update.
I also suggest you download a copy of ATV2 iOS 4.1 in case you need it in the future to restore: