More details have emerged from the High Court ruling that R4 cartridges have been banned in the UK.
Eurogamer has obtained a copy of the High Court of Justice Chancery Division's judgement in favour of Nintendo against defendants Playables Limited and owner Mr Wai Dat Chan.
The case concerned "a number of different types of devices imported and dealt in" by Playables.
Devices are defined as those which "enable Nintendo DS users to play unlawful copies of Nintendo DS games which they have downloaded using the internet".
That's what Nintendo means when it says "game copiers".
But what, exactly, has been made illegal?
According to the report, the R4 DS, M3 DS, DS One Supercard, DSTT, DS Linker, Acekard, CycloDS Evolution, N5 and EZ devices were under scrutiny.
Some are still listed on Playables' website.
They contain either built-in memory or a further slot of their own which accommodates a micro-SD flash card.
They also contain circuitry, software and data that enable them to pass the tests performed by the Nintendo DS to verify the game inserted is genuine.
The case concerned the Copyright Designs and Patents Act 1998, and Nintendo's claim that games were copied into the random access memory in the course of using Playables' devices.
The judgement reveals the steps Nintendo takes to prevent loading unlawful copies of its games:
The shape of the connector arrangement of the slot on the DS and the corresponding shape of the game cards designed to fit into it; the boot up software permanently stored on the Nintendo DS, which checks for the presence on an inserted card of the Nintendo Logo Data File (NLDF) and prevents execution of programs present on the inserted card if the NLDF is not detected; and the use of shared key encryption technology and scrambling to enable the DS to detect whether game cards are authentic.
Are all "effective technological measures" taken by the Japanese company to protect itself.
The judge found in favour of Nintendo because it proved the devices circumvented them.
So, what does this mean?
It means that it is now illegal to manufacture, import, distribute or sell in the UK any device that is "primarily designed, produced, adapted or performed for the purpose of enabling or facilitating the circumvention of the ETM employed by Nintendo to protect its copyright".
Simply owning a relevant devices is not illegal. But it's probably best not show it off to your mates.
Apparently, Nintendo has seized "more than 165,000 game copiers intended for" Playables. That’s a lot.
The Hon Mr Justice Floyd, who made the ruling, wrote: "Each game card has the code relevant to the NLDF installed on it. I cannot see how it can be said that Nintendo authorised the copying of this into RAM.
"The accused devices are much more than the reel-to-reel tape recorders in CBS v Amstrad (1998).
"They are templates for infringement."
Playables had argued that it did not know or have reason to believe that the devices would be used to make infringing copies.
It also said there are lawful uses for the devices, such as playing homebrew games.
The judge said neither argument had merit.
"It needs to be kept in mind that the focus of this requirement is on circumvention.
"The fact that a device may be used for a purpose which does not involve infringement of copyright does not mean that the sole intended purpose is not the unauthorised circumvention of a technical device."
Wai Dat Chan did not appear and was not represented at the ruling.
Chan did not respond to requests for comment from Eurogamer.