In a filing to the Securities and Exchange Commission, TiVo has warned that a new open source license could cause big trouble for the company.

TiVo is based on Linux, an open source operating system. And for the most part, TiVo's turned a blind eye to hardware hackers, allowing users to put larger hard drives in their boxes or enable networking.

But when it comes to software, that's another story. TiVo has always walked a fine line with content owners, and has included copyright protection that limits what you can do with television recordings. To that end, TiVo includes software that cripples the machine if you try to manipulate the source code.