In March, Apple was ordered in an Eastern district Texas court to pay just over $300 million to Personalized Media Communications (PMC) after a multi-year lawsuit over alleged DRM infringements. Today Apple won a ruling that voids the March verdict with a judge essentially finding Personalized Media guilty of patent trolling.

Reported by Bloomberg, the patent at the basis of the $308 million March judgment has now been found to be “unenforceable” after Apple appealed the earlier ruling.

PMC’s patent application goes back to the 1980s but none were awarded until 2010 and on. This strategy was found to constitute “an unreasonable delay and an abuse of the statutory patent system,” Gilstrap wrote.” Another name for the strategy is “submarine patents.”

Personalized Media Communications LLC’s patent for digital rights management is unenforceable because the company intentionally delayed its application at the U.S. Patent and Trademark Office so it could get more money later, U.S. District Judge Rodney Gilstrap in Texas ruled.

The court even saw internal PMC documents naming Apple as one of the “natural candidates” to target way back in 1991.

Gilstrap relied on a June ruling from the nation’s top patent court that made it easier to challenge so-called submarine patents, where applicants would delay issuance of a patent until after an industry had adopted the technology and infringement suits would be more profitable.

The company pursued a strategy to ensure this and other patents wouldn’t be issued until “infringement becomes widespread in an industry,” according to internal documents cited by the judge. Apple, a 1991 document showed, would be one of the “natural candidates” for such a program, along with Intel Corp., International Business Machines Corp. and Microsoft Corp.