It seems the battle between Psystar and Apple grows increasingly hostile as time progresses. Psystar now claims that legally purchasing copies of Mac OS X, allow for the operating system to be distributed on unofficial machines.

The Florida-based company wrote a seventeen page rebuttal in response to Apple’s claims and filed it in a San Francisco court last week accusing Apple of violating copyright laws by requiring Mac OS X to run only on official hardware. Psystar also claims that because it purchased legitimate copies of the Mac operating system from official retailers, that under the doctrine of first sale, the company doesn’t need Apple’s permission to resell them.

The battle between the two companies began back in July when Apple sued Psystar for breaching copyright laws. Psystar fired back a month later. Apple stands by its claim that the Mac OS X licensing agreement forbids installation on any unofficial hardware.

The full case will go to trial in April.