The early versions only gave access to DVD video mode.Which isn't available from TT anymore. Besides, the version of DVDX that is good is from a much older version. It allows access to the SEEPROM for example.
The later versions additionally use AHBPROT to give access to the restricted registers. Nothing more than what HBC already does.
Daco actually published a "patch" containing all the crap he used in the installer: http://dacotaco.com/...ibahbprot.patch
Not sure how he thought this makes things better when it's quite obvious (even by his own admission) that the patch contains code that he doesn't have permission to use.