This has generally been achieved by using certified DualDisc plants that are also licensed to make DVDplus discs.
Although theoretically almost identical, DVDplus discs have so far appeared in practice - despite claims to the contrary - to measure as having slightly thicker CD-compatible layers than DualDiscs (though not sufficiently thick to make them conform to CD Red Book specifications).
This also meant that there were no limitations to the CD-compatible side's playing time as was the case with early DualDiscs.
Despite these factors, return rates for both of the dual-sided disc products as a result of either sticking or non-playability are claimed to be extremely small.
The only European patents granted for the DVDPlus concept have either been withdrawn, revoked or allowed to lapse.