Here is what I believe is the situation.
2005 RX 330 has Gen 4, version 4.2 firmware and maps -- override works
Gen 4, version 5.1 firmware and maps -- override works
Gen 4, version 6.1 firmware and maps -- override fails
Gen 4, version 7.1 firmware and maps -- override fails
Gen 4, version 5.1 DVD has a file named loading.kwi. This file changed in version 6.1 which is why the override fails.
The hybrid DVD takes the Gen 4, version 6.1 files and replaces its loading.kwi with the loading.kwi from the version 5.1 DVD. One has to burn this on DVD+R DL media at no more than 4X (burner must be able to DVD+R).
Gen 4, version 6.1 + loading.kwi(version 5.1) = hybrid 6.1 DVD -- override works
Theoretically, this will work with the version 7.1 firmware, but I have not had time to research that issue completely. My initial thinking is that some other changes have occurred that may prevent this hack from working.
Also, once one loads one version the only way to go back a version is to remove fuse TV-1 for the Nav unit which powers it off and it will then do a complete reload when power is restored. The same could be accomplished by removing the battery cable and then replacing it.
The problem becomes one of finding a version 5.1 and 6.1 DVD. I did find this site for downloading loading.kwi but have not had time to study it.
So much for now. It is late.
HTHs
YMMV
Mike
Great post Mike !! that makes sense... now if I could only find a newer version than my 2005 RX330 Gen4 ver4.2.. I could give it a try..