What makes a Safedisc 2 compatible writer?

[Clong]

(posted in several forums)

What properties of a burner make it Safedisc 2 compatible(universal cd)?

I thought that it had to read/write RAW-DAO+Sub 16(at least), and write EFM correctly.

What's throwing me off is that CloneCD's website says that the Phillips CDD4801 writer that I'm looking at($50 locally) only reads data/audio in RAW mode(no sub) and burns RAW-DAO+Sub 16 and correctly writes EFM.

I've seen several places say that the Phillips mechanisms, and this one in particular, are definitely SD2 compatible. What gives? The SD2 info is in the subchannel right? Wouldn't the drive have to be able to read that info from the subchannel to make a perfect universal copy? Is CloneCD's site wrong, or is it my assumptions? I also see other drives there that don't write EFM correctly, yet they are apparently also compatible? At least in that same burner...

Lastly, just what does make a burner partially SD2 compatible(cd works only in the burner)? Is it just the firmware/mechanism combination? Maybe different mixtures of the above hardware properties?

Hopefully we can come up with an SD2 super FAQ that covers everything, since I have yet to see one good enough. I'd love to see someone come up with a searchable database that had all the stuff we look for in a burner, along with more complete re-branding info.

Thanks for your help.