Just like Chronic Dev Team’s GreenPois0n, the Windows counterpart of PwnageTool 4.1 known as Sn0wbreeze 2.1 has been fully open sourced and it’s source code is available to public for free. What’s the point of making it open source? You can modify the tool according to your own liking or even improve it for the betterment of the jailbreaking community under the terms and conditions laid down by General Public License (GNU).
For those of you who don’t know, like PwnageTool for Mac, Sn0wbreeze for Windows can be used to create custom firmware files for iOS 4.1 without the upgraded baseband so that you can unlock iOS 4.1 (05.13.04 baseband) with existing version of Ultrasn0w.
Since instructions for jailbreaking iOS 4.1 using Sn0wbreeze are almost exactly similar to the last release, you can follow the instructions posted here (from Step 1 onwards; Spirit2Pwn is not needed) to jailbreak the above mentioned devices on iOS 4.1 using Sn0wbreeze 2.1. Instructions on how-to enter DFU mode on Apple TV 2G can be found here.
Download Sn0wbreeze 2.1 Source Code.