Thanks a lot for the fast reply!
Yeah, I did ran the Compat Fixer from USB (I put every game there too) and moved the whole Compatibility folder to HDDX through Freestyle 3 File Manager. But after doing it, I didn't even got the Xbox splash screen when I ran my Halo 2 copy even though before I try the tutorial I get into the splash screen and the "blocked by Family Settings" error shows up (keep in mind I've never turn on the Family Settings and it is still on Off).
I'm just wondering if I screwed something up in regards to the contents of HDDX partition. Just to clarify, after running (and rebooting) Compat Fixer, the HDDX is supposed to be empty and all I need to do is copy the Compatibility folder into it, right?