AVM is a company selling modems/routers. Cybits provides a modification that adds functionality. AVM is claiming that normal Linux kernel operations like rmmod are illegal without AVM’s permission. They claim AVM’s implementation of Linux is a copyrighted work and Cybits does not have the right to modify it even though the Linux kernel is provided under GPL v 2. GPL v 2: “By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software–to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation’s software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Lesser General Public License instead.) You can apply it to your programs, too.”
AVM is out to lunch on these issues but their lawyers want to be paid for this useless legal effort. They no longer own the product they sold and they should not be concerned by what software users want to run on them. Cybits may be interfering in after-sale maintenance or warranty but Cybits is not violating copyright.