As you requested in the comments section, I created and released the Setup.App patch for iOS 9.3.5 (Genoa) for iPhone 4S and I also explain this video how Odysseus works (for Downgrades using iBSS, iBEC and ASR patches) and where you should seek help during your downgrade or CFW creation.
A comprehensive F.A.Q. page for Odysseus and Odysseus OTA downgrade for iOS is available on the iPhone Wiki. I linked it down bellow as some people tend to misinterpret the patches and how they should be used and when.
The Setup.App patch for iPhone 4S is compiled in a manner that should avoid giving any "free space" related error.
==Download Section==
Setup.App Patch: https://mega.nz/#!g4N21CwJ!90SgzXvlhT7UPL1xhcXE2XFz49oM7RDS31GmpA_Ni-w
==Additional Important info==
https://www.theiphonewiki.com/wiki/Odysseus
https://github.com/ramytuki/ios-kexec-utils