Blackberry manufacturer Research In Motion (RIM) has dropped Howrey as its lead litigation counsel in favour of Kirkland & Ellis for its patent fight with Visto.
Visto has alleged that RIM infringed four of its patents, and is looking for an injunction and damages in a court in Marshal, Texas.
Kirkland partner Linda DeBruin is leading the defence team, which has taken an aggressive approach to the litigation. RIM has counter-sued Visto, asking a federal court in Dallas to dismiss the case.
Visto issued its proceedings against RIM in the same court where it won $3.6m (£1.93m) in a similar patent dispute against Seven Networks at the end of April. Howrey partner Henry Bunsow represented Seven Networks in its dispute with Visto.
California firm Manatt Phelps & Phillips is representing Visto against RIM, the same firm as in the Seven case, with Texas firm McKool Smith acting as co-counsel.
Sam Baxter, who is leading the McKool team, said success against Seven spurred the litigation: "It has to do with the fact we won [the Seven] case. The jury seemed to find all the patents valid, and that vindicated what we thought."
Visto has filed similar patent complaints against Microsoft, Good Technology and Smartner within the last year.