The three-year battle between TiVo (NASDAQ:TIVO) and DISH Network (NASDAQ:DISH) rages on.

Shares of TiVo fell by as much as 21% on Friday, ultimately closing down 9%. The culprit was a court ruling that allows satellite television provider Dish to keep marketing its DVR boxes to subscribers through at least mid-February.

It's a rare victory for Dish Network and original parent EchoStar (NASDAQ:SATS), which have typically come up short in their assertion that Dish's boxes do not trample on copyright-rich TiVo's intellectual properties.

TiVo has already collected nearly $105 million in damages from EchoStar. Now it just wants the boxes off the market, and turned off for existing Dish subscribers.

TiVo's not simply being a meanie. It has patents to protect, and other DVR marketers, like rival satellite television provider DirecTV (NYSE:DTV) and cable television giant Comcast (NASDAQ:CMCSA), paying TiVo to license its time-shifting technology. The last thing it needs is for renegade rivals to think they can get away without paying.

Dish claims that it has come up with a firmware "design-around" that doesn't impede on TiVo's tech. The court gave Dish three months to prove it.

Is that really worth it, Dish? Satellite television is a growing industry, but you wouldn't know it from Dish's numbers. The company lost 10,000 net subscribers in its latest quarter. Naturally, few of the defections are from concerned subscribers who feel that their recorders will get shut off, but does Dish realize that all of these legal scuffles still have an impact on the company's brand? With 13.8 million subs, Dish serves a smaller audience than other satellite broadcasters like DirecTV and Sirius XM Radio (NASDAQ:SIRI), but it's still roughly three times the subscriber base of TiVo. After a while, Goliath must get tired of the repeated hits from David's slingshot.

Play nice with TiVo, Dish. Heck, even buy TiVo if you think you can swing it. All of the fighting is only hurting the Dish brand, while solidifying TiVo's patents.

Don't get me wrong. If the software update truly tiptoes around TiVo's intellectual property, it's a battle worth duking out for Dish. But once the fisticuffs spill into the audience, I doubt subscribers or shareholders will be too eager to stick around and spectate.

More tales of the TiVo-lution:

Longtime Fool contributor Rick Munarriz does love his TiVo and he does own shares in TiVo. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.