AVM Computersystems, a manufacturer of DSL routers including the popular FRITZBox, is trying to stop Cybits, a maker of web-filtering software, from changing the code which is present in the firmware of its routers.
The code comes partly from the Linux kernel; given this, the terms of the GPL would extend to the entire codebase giving users the freedom to modify it and use the changed version if they so wished.
AVM filed two actions against Cybits last year, claiming that when people installed Cybits' filtering software on AVM routers, it changed the routers' firmware, and, hence, infringed on AVM's copyright.
During an oral hearing on June 21, the two parties and Harald Welte, the founder of gpl-violations.org and an intervener in the case, discussed the three aspects on which AVM bases its claims.
According to a statement from the Free Software Foundation Europe, the discussion revolved around trademark and competition law issues. While AVM did not deny that GPL-licensed software installed on its routers may be changed by users, it maintained that the reinstallation of such altered software was not allowed.
AVM argued that if this changed software reached other users, they might conclude that any changed functionality was due to AVM when in reality it was due to changes wrought by Cybits. Thus, AVM said, its trademark rights were being violated and this also meant unfair competition.
AVM also argued that routers are not normal computers on which users could install additional programs; it was a product that was designed not to be changed. Hence, AVM argued, it did not have to put up with changes being made to the router firmware.
Cybits and Welte said the issue of trademark violations did not arise as Cybits was not using AVM's trademarks. And the question of unfair competition did not come up because the licence permitted Cybits to change the firmware kernel. They also argued that a router was indeed a computer.
According to the FSFE statement, the court was sceptical about restricting the rights of users to make changes in the Linux kernel. The court also said that when the firmware was seen as a whole, as AVM seemed to do, the entire firmware would be covered by the GPL. The court made no clear statement on the competition law arguments.
No decision was made on the day and further written pleadings can be submitted. The court would then either make a direct decision or begin hearings, the FSFE statement said.
Comment has been sought from AVM. The company did not respond to an earlier request for comment, made when the first report of this case was filed.