Mac clone-maker Psystar on Thursday filed an amended complaint against Apple, arguing that Apple is misusing copyright by tying its OS X operating system to Mac computers.

Judge William Alsup gave Psystar the the green light last week to file an amended complaint in its long-running legal battle with Apple over running OS X on non-Apple hardware, removing the antitrust complaint and moving ahead with the copyright misuse case.

To prove its copyright misuse claim, Psystar refers to Apple's End User License Agreement, which states that users agree to install the Mac OS only on an Apple computer. The lawsuit claims this overextends the boundaries of the Mac OS copyright.

In the amended complaint, Psystar also quoted Apple Senior Vice President of Worldwide Product Marketing, Phil Schiller's, statements in 2005 that Apple wouldn't do anything to stop people from running Windows on a Mac, but it wouldn't allow the Mac OS to run on non-Apple hardware.

To prevent someone from running OS X on another system, Psystar alleges that Apple embeds code in the operating system to cause a kernel panic if non-Apple hardware is recognized.

Psystar originally sought to charge Apple under antitrust laws because it said Apple "possesses monopoly power in the Mac OS market." However, the antitrust argument didn't pass muster with Judge Alsup.

In dismissing the antitrust charges, the judge said "Psystar's allegations are internally contradictory."

Apple filed a copyright infringement suit against Psystar in July 2008, starting the back-and-forth legal battle that has lasted for almost eight months.

The trial is set to begin on November 9, 2009.

Apple has 20 days to respond to the amended complaint.

The Psystar Open Computer, as seen in the Macworld Lab

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