Research In Motion Ltd. said Wednesday it is preparing workarounds to keep Blackberry services in the United States up and running, in the event a court issues an injunction against the company as a result of ongoing patent litigation.

A new chapter emerged in its dispute with NTP Inc., earlier Wednesday when a ederal judge invalidated a $450 million settlement between RIM, maker of the Blackberry email device, and the Arlington, Va., patent holding company.

The ruling was a victory for NTP, which had argued that the settlement was never finalized. As a result, U.S. District Judge James R. Spencer could next consider whether to reissue an injunction preventing RIM, based in Canada, from offering Blackberry service in the United States.

In a statement, RIM said it was prepared to argue against the injunction, but also said it was ready to make changes to its technology to avoid the alleged patent infringement.

"As a contingency, RIM has also been preparing software workaround designs, which it intends to implement if necessary to maintain the operation of BlackBerry services in the United States," the company said. "Further details will be made available if such implementation becomes necessary."

Besides NTP's expected request for a BlackBerry ban, the U.S. District Court is also expected to reconsider RIM's arguments that U.S. patent laws do not apply to it because it operates in Canada, an argument that the courts so far have rejected.

RIM is trying to reverse its loss of a patent-infringement suit filed by NTP, which claimed RIM infringed on several patents, including NTP's radio-communications technology. A federal court in Virginia had ruled against RIM in 2003, but that decision was reversed on appeal and sent back to the Virginia court for reconsideration.

RIM had agreed in March to pay $450 million, and license NTP technology covered by all current and future patents. That deal, however, was invalidated on Wednesday.