Summary of the case so far

The dispute between "AVM Computersysteme Vertiebs GmbH" (AVM) and "Cybits AG" (Cybits) concerns all providers and users of Free Software which uses the GNU General Public License (GNU GPL). Berlin based company AVM is a major manufacturer of digital subscriber line (DSL) terminals, such as the FRITZ!Box router, and uses the Linux kernel as a part of their production firmware. Cybits distributes the Internet filtering software "Surf-Sitter DSL", which is intended to protect children from inappropriate media on the web. The Surf-Sitter application downloads FritzBox software to the user's computer, modifies it and then reinstalls it back on the FRITZ!Box.

AVM took legal action against Cybits at the regional court of Berlin in order to prohibit Cybit from modifying the original firmware of FritzBox and loading it back to the DSL terminal – and as part of this legal action included software parts licensed under the GNU GPL.

In the opinion of Mr Harald Welte, a programmer and one of the Linux Kernel's developers, AVM's claim is illegal. As both AVM and Cybits are his licensees, he joined the legal proceeding as an intervener, and filed a third party intervention (pdf, German).

The preliminary case concerning this dispute has already been closed, and the outcome now depends on the currently pending main proceedings.

The preliminary case

In January 2010, AVM applied for preliminary injunctions against Cybits. Preliminary injunctions seek to find a temporary solution in a legal dispute; for urgent reasons, evidence is not taken but the parties involved must prove facts. In most cases, preliminary injunctions are chosen to force a rapid decision.

AVM justified its request for preliminary injunctions against Cybits, with an alleged infringement of copyrights and competition law. The court accepted the request and Cybits lodged an appeal thereafter.

Mr Welte, Free Software developer and founder of the website gpl-violations.org, learned of the case and joined the legal dispute as an intervener. The ability to join as an intervener is allowed by both AVM and Cybits being his licensees: both companies use the applications MTD and iptables/netfilter, which are included in the Linux kernel. In the opinion of Mr Harald Welte, AVM's legal action towards Cybits infringe on the GNU GPL as well as his personal copyrights.

One of AVM's intentions is to prohibit Cybits from modifying the Free Software kernel and installing it back on the DSL terminal. AVM's request was:

The defendant [Cybits] is obliged to refrain from supplying, distributing and/or operating the "Surf-Sitter-DSL" software, as far as this software edits and modifies the firmware, which is embedded in DSL-routers produced and distributed by the applicant [AVM], especially FRITZ!Box Fon [...], and as far as it further uses unmodified or modified parts of it.

With this, AVM's intention is to judicially prohibit Cybit from modifying the GNU GPL licensed software on its DSL terminals. The GNU GPL requires that anyone is authorised to use, study and modify software which is licensed under it, and to distribute it in an original or modified form. AVM thus utilises Free Software for its products, but violates the software's license terms. Therefore the license's termination clause comes into effect and AVM is no longer authorised to distribute the Free Software embedded in its products.

AVM justified its position using three arguments. First, they stated that their whole product software must be regarded as an entity under AVM copyright, and that this entity must not be modified. The position Mr Welte took was that the whole product software would in that case be a derivative work according to the GPL, and thus the whole product software should be licensed under the GNU GPL. AVM then switched to a second argument: that the software embedded on its DSL terminals consisted of several parts. According to Mr Welte, AVM could then not prohibit anyone from modifying or distributing the GPL licensed software parts. The final argument by AVM was that the software on their DSL terminals is a composition of several different programs, which, due to the creative process, would be a protected compilation and thus under the copyright of AVM and not affected by the copyleft of the GPL.

The Superior Court of Justice Berlin revised the original modification prohibition of the FRITZ!Box firmware, confirming it only as far as the modified software returning incorrect values, e.g. if the status of the DSL terminals displays incorrectly as being "online" or "offline". With this, the principle position of Mr Welte and FSFE has been confirmed.

Related documents

Principal proceedings

AVM has furthermore filed principal proceedings against Cybits, which is currently pending at the Berlin regional court. The main proceedings aims at an ultimate settlement of the lawsuit. The court is not bound to the decision from the preliminary case as different facts can be taken as a basis due to the possibility of a more comprehensive chance to produce evidence. The hearing will take place on June 21, 2011.

The arguments given by the parties in the main proceedings thus far refer to those given in the preliminary case. Because Cybits did not react to a legal document in time, a default judgement was given, prohibiting Cybits from modifying the software of the DSL terminals. Cybits lodged objections against this judgement.

Again, Mr Welte submitted an application to the court to be admitted as an intervener.

Oral Hearing - 21st June 2011

On June 21st, the District Court of Berlin held the first oral hearing in the law suit of DSL router manufacturer AVM against software producer Cybits. In the hearing, the parties and defendant’s intervenor, Harald Welte, discussed all three areas of law AVM bases its claims upon: Copyright, trademark and competition law.

The focus of the hearing, however, lay less on the area of Copyright but more on trademark and competition law issues. AVM doesn’t deny that the GNU GPL licensed software installed on the routers may be changed by the users, but maintains the opinion that no altered software may then be reinstalled on the routers. AVM relied on two main arguments:

AVM routers with the software changed by Cybits' software might possibly reach third parties who would have no knowledge of the firmware changes and who may therefore attribute possible router functional changes to AVM even if they were actually caused by the software of Cybits. Therefore, the trademark rights of AVM were infringed. This also constituted an act of unfair competition.

Furthermore, AVM argued that routers are not normal computers on which users can install additional programs, but rather products designated to not being changed. Therefore, AVM did not need to tolerate a change of the router firmware, even of the kernel.

The representatives of Cybits and Harald Welte explained that these arguments have no basis and that a trademark infringement should be ruled out because Cybits doesn’t use the trademarks of AVM. There was no unfair competition either, as Cybits was precisely permitted by Copyright to change the firmware kernel. In particular, the GNU GPL explicitly required that the reinstallation of changed software must be made possible. And, of course, a router was a computer, the lawyers explained, whose firmware can and may be changed by those interested as long as they have sufficient copyright authority (e.g. by the GNU GPL).

Decision - 8th November 2011

On November 8th the Regional Court of Berlin [Landgericht Berlin] issued its decision (PDF, German). The court has particularly denied that Cybits has infringed AVM's copyright by distributing its "Surf-Sitter DSL" software. According to the judge the AVM DSL router's firmware is a collective work. The GNU General Public License (GNU GPL) clearly states that the GPL parts contained in the firmware can be lawfully modified and reproduced. Thus it is acceptable that these parts are downloaded from AVM and edited during the installation of the Surf-Sitter software.

The trademark claims were also rejected. The fact that in the router's interface the trademark "Fritz!Box" is still visible after the installation of Surf-Sitter does not constitute an infringement. It also unfolds from the reasoning that a modification of the GNU GPLed parts of the firmware does not trigger any competition claims. The Regional Court therefore confirms that it is in general permissible to modify firmware parts under the GNU GPL and to newly install these modified versions.

The granting part of the verdict which parallels last year's judgment of the Superior Court of Justice is mainly based on the idea that the customers impute wrongly displayed information about the internet connection and the status of the parental control to AVM. Cybits must remove this misinformation if they wish to sell their product. In contrast, modifications of the firmware as such are allowed.

The verdict is not yet final. The parties can still appeal the decision.

Verdict in the case of AVM vs. Cybits confirmed the view of FSFE

01 December 2011:

Court rejects AVM´s claims opposing third party modifications of GPL software

07 November 2011:

FSFE on AVM vs Cybits: A small computer is still a computer

22 June 2011:

AVM enfreint la licence du noyau Linux

20 June 2011: