In today's update, we fixed a couple of issues you found on the Setup.App Patcher module of the Firmware Manager X. With this new version, you should no longer get any free space-related issues from TransMAC when you put the created patch.
Also, this new version has some new verification steps in place to prevent usage of wrongly extracted Setup executable (yes, the 0 bytes issue) and tells you whether you extracted it right or wrong and what you can do about it. This new enhancements helps you to build the patched file easier.
If you didn't see the previous video in which we introduced the new feature and how to use it, I definitely recommend you to do so before (or after) watching this video. Here it is: https://youtu.be/84vp72oTlJE
Also, if you don't know how to properly extract the Setup.App to prevent 0bytes issue, here's how: https://youtu.be/rncCa3_F_dY
Learn some iOS Reverse Engineering (You will Thank me later):
Firmware Manager v26.5: https://www.theiphonewiki.com/wiki/Firmware_Manager