Taiwanese handset manufacturer HTC has appealed against the U. S. International Trade Commission’s initial ruling that favored Apple in S3 Graphics patent claim.

The U. S. International Trade Commission ruled on Tuesday previous week that the Cupertino-based gadget maker Apple’s Mac OS X system had violated two S3 texture compression patents, but the commission also ruled that Apple’s iOS-based iPhone and iPad hadn’t infringed on any patents of S3 Graphics.

TC acquired S3 Graphics on 6th of July in a deal worth $300 million in order to expand its patent portfolio.

HTC also appealed another ruling that stated that Apple's MAC OS did not violated S3's patents for a graphics processor manufactured by NVIDIA. According to the commission, the patents were covered under an earlier cross- licensing agreement, but the Taiwanese firm disagrees with that ruling.

On July 15, in a separate case between Apple and HTV, the commission ruled HTC infringed on two Apple patents.

The tug of war between world's largest smartphone maker Apple and world's fifth-largest cell phone manufacturer HTC started in March 2010, when the Cupertino-based gadget maker sued the Taiwanese firm for 20 instances of patent violations.