Jay-Z is staking legal claim to the master recordings of his iconic debut album … and it’s a “buyer beware” notice, of sorts, to anyone getting ready to drop more than $1 million to buy Damon Dash‘s share of Roc-A-Fella Records.

TMZ Hip Hop has learned Jay’s attorneys just made a legal filing that might normally fly under the radar, but here’s why it’s suddenly very relevant. As we first reported, Dame’s third of Roc-A-Fella is going up for auction later this month, and the label’s only real asset is Jay-Z’s 1996 album, “Reasonable Doubt.”

While Roc-A-Fella currently holds the copyright on the record and all its tracks … Jay’s attorneys have now filed notice that those rights will revert to one Shawn Carter/”Jay-Z” in 2031.

Even though Jay and Dame ain’t exactly vibing these days, this legal move isn’t about revenge, it’s just biz — the rights would have gone back to Jay 35 years after the record was released, anyway. His lawyers have just filed the paperwork to make it official.

So, what does this mean for the August 29 auction? Whoever ends up winning Dame’s shares — minimum bid is $1.2 million — will enjoy one-third of all “Reasonable Doubt” revenues … but only for about the next 6 years and change. Then it’s all Jay’s.

Of course, this could potentially have a chilling effect on how high the bidding goes.

We broke the story … there would be a limited shelf life, financially speaking, for whoever wins the auction, and now Jay-Z’s declared the expiration date.