There are many ways to fight piracy: Technical means where you try to design your system to be “unbreakable” or you update it to render current circumventing solutions inefficient. Or you may use the legal means where you sue the pirate.
In its fight against R4, Nintendo uses both methods. R4 cards (and R4i) are among the most popular cards for pirating Nintendo DS (and Nintendo DSi). This card is inserted in the cartridge in place of the legit game. You may download the games (so called ROMs) from the Internet, store them in a standard flash memory, and here you play. In other words, you can find on the Internet, about all (if not all :Sad: ) the published games and run them for free on your DS with the R4. The price of these cards being ridiculous, you may guess the huge success. I must confess, that at least in France, R4 is rather successful.
Nintendo has attempted (and is currently attempting) several ways to thwart R4. Unfortunately, not with great success.
But they are successfully on the legal battlefield. In February, Nintendo got GadgetGear, an Australian company, to pay A$620,000 (about 414K€ or 567K$) by way of damages. Since 2008, Nintendo pursued more than 800 actions against resellers. Fighting local resellers is a good strategy if this generates good frightening examples. With the easiness, to find local resellers on the Internet, it seems that Nintendo needs more successful trials to scare the resellers. Resellers are rather operating openly.
For more details, see the press release.
Game security is really a tough job.