The U.S. District Court for the Central District of California at Los Angeles, issued a preliminary injunction against VIA and AOpen in September 2003 over copyright infringement claims. In its aftermath, VIA and AOpen filed an appeal with the U.S. Court of Appeals for the Federal Circuit, seeking to reverse the preliminary injunction order. Additionally, they also filed a motion to stay the preliminary injunction pending appeal. Even though the Federal Circuit has not ruled on the appeal itself, it issued an order on January 22, 2004, denying VIA and AOpen’s motion to stay the preliminary injunction. In view of this decision, MediaTek has announced that during the period in which the preliminary injunction is in force, VIA is required to notify and request from all of its customers to stop importing into the U.S., any products containing CD-ROM controller chips or firmware, or any other derivative or substantially similar software belonging to MediaTek, until a Californian Court comes to a decision regarding this case.

This follows hot on the heals of a similar action by VIA, when back in June of last year (2003), VIA Technologies Inc. filed suit against MediaTek Inc. for patent infringements over its optical storage controllers, alleging that MediaTek's DVD-ROM, CD-RW and CD-RW/DVD controller products infringed on VIA's US patent. Furthermore, VIA sought for a preliminary injunction on the sale, display and import of MediaTek's products into the US, with the possibility of compensation and the destruction of MediaTek's inventory in the US.The suit was filed in the US District Court in San Francisco.

MediaTek has further requested that any companies using any products infringing on its technologies, should stop their use in order to protect MediaTek's property rights.