That is highly unlikely given he is using the correct patches for that kind of setup. Also most people do not typically chainload as most, if not all, distributions of Hekate have fss0 as the default option for launching CFW.
Are you using MacOS?
Unfortunately SDSetup no longer provides patches so you will have to download them separately which can be found
here. There is no "safest firmware" as the higher firmware versions break various homebrew applications and sysmodules but are required to play newer games. Having an emuMMC loaded with a different firmware version mitigates this issue.