Works fine for what? NTFS has always been readable by the Humax without mods, and the custom software has added support for writing, but I have yet to hear of anyone actually able to record to one.
The custom software runs with errors from a FAT32 drive, and is not expected to work properly from a NTFS drive even if core functions from the NTFS driver were moved from the custom packages into the custom firmware. These points are important for HD-FOX with no internal (Ext3) drive. To support recording and the custom software, HD-FOX users are recommended to use an external Ext3 drive (formatted by the HD-FOX), or for custom software only (no recording) a USB stick formatted Ext2.
Are you saying different?