As promised, the hacker and homebrew developer Jordan "Smealum" Rabet has revealed how the YouTube app for Nintendo 3DS can be used to launch hombrewed 3DS games.
The exploit is of particular value to homebrew enthusiasts because the YouTube app is free and, as of now, it's still on the 3DS eShop. Earlier, Rabet had found an exploit to launch homebrew apps through the game IronFall: Invasion, which also was free to download. Nintendo quickly removed that from the eShop, although hundreds of thousands of copies of it have been downloaded since its February launch.
Rabet, in the following YouTube video, shows the launcher in action. He insists that "this launcher does not in any way let users run pirated 3DS software." TubeHax, as the exploit is called, also allows users to run out-of-region gamecards and use custom themes in the 3DS home menu, as well as SNES ROMs through an emulator.
Typically Nintendo has resolved these exploits with a firmware update. The latest firmware for 3DS is 9.9.
Rabet was behind a similar exploit last November, Ninjahax, which took advantage of the puzzle game Cubic Ninja by AQ Interactive. It, too, was taken down from digital storefronts until Nintendo could patch the 3DS' firmware. All this led to GameStop raising the price on used physical copies of Cubic Ninja — which launched in 2011 — to $39.99 from $5.
Homebrew has always been treated as a four-letter word by Nintendo, particularly for the 3DS. Piracy was a constant problem for Nintendo during the run of the original DS. The R4 cartridges that enabled piracy were outlawed in a number of nations in response.