Requirements for breaking 4 GB HD limit?

[Spidey]

I had problems with the fastfilesystem delivered with OS3.5 and OS3.9
I too have a SCSI 9 GB harddrive, but at first I couldn't get it to
work with the fastfilesystem. I ended up getting a
fastfilesystem-patch from Aminet: http://www.aminet.net/disk/misc/ffstd64.lha

Patched my old 3.1 filesystem and now I have a working harddrive of 9
GB.
I guess the FFS of 3.5+ doesn't work for SCSI harddrives, only IDE
drives?