IFaith

iFaith is an open source SHSH dumper for the Windows family of operating systems written by iH8sn0w. It works on all devices that are susceptible to the limera1n exploit (all devices before the iPad 2). This is useful if you receive a device with old firmware on it that you want to be able to restore. Even if Apple doesn't sign that firmware anymore, you can backup the SHSH data directly from the device, so that you can install the firmware later again to avoid upgrading the firmware.

Source Code
The source code of iFaith 1.2 is available under the GNU General Public License v3. Other versions are not available.

License
What is interesting is how iFaith uses xpwn (xpwntool and hfsplus) while being able to be closed source. The reason is that the GNU GPL v3 requires derivatives of GPL software and programs utilizing GPL libraries (static or dynamic) to be under the GNU GPL v3 or (at their discretion) a later version. iFaith works around this the same way macOS does - by using a compiled executable, not a library.

Credits

 * iH8sn0w - author
 * geohot - limera1n Exploit