51-year-old Canadian hacker Gary Bowser has pleaded guilty to multiple hacking charges, must now pay $4.5m, and could also face up to 10 years in jail.
Bowser had been a long-term enemy of Nintendo for his role in Team Xecuter, a group which designed and sold console modchips to allow the play of pirated games.
Torrentfreak reports Bowser recently changed his plea to guilty, admitting charges of circumventing technological measures and trafficking in circumvention devices.
Bowser admits working with Team Xecuter from June 2013, with whom he "knowingly and willfully participated in a cybercriminal enterprise that hacked leading gaming consoles" via devices such as the Gateway 3DS, Stargate, TrueBlue Mini, Classic2Magic, and the SX.
His plea agreement includes the acknowledgement he "developed, manufactured, marketed, and sold a variety of circumvention devices that allowed the enterprise's customers to play pirated versions of copyrighted video games, commonly referred to as 'ROMs'."
Team Xecuter earned "at least tens of millions of dollars" from the sale of its piracy-enabling devices, the document reveals, from which Bowser took around $320k per year. The company had used the defense that its devices enabled homebrew development - while also asking for a license fee to unlock the playing of pirated games.
Nintendo has had Team Xecuter in its sights for some time, but things escalated last October when the US government issued federal charges against Bowser and alleged fellow Team Xecuter members Max Louarn, a 48-year old French national from Avignon, and Yuanning Chen, 35, from Shenzhen, China.
Bowser was arrested and deported to the US after being found in the Dominican Republic. Louarn was arrested in Canada, from which the United States is seeking his extradition. Chen is still at large.