A software update for the Nintendo 3DS appears to have blocked a backdoor hack that allowed users to play unlicensed games on the handheld.

In November, homebrew games enthusiast Jordan Rabet revealed that 3DS owners could play unofficial games on the handheld by applying an exploit that he named NINJHAX. Curiously, the process requires a copy of Cubic Ninja, an obscure Ubisoft platform game released in June 2011.

However, 3DS firmware update 9.3, which rolled out on Tuesday, appears to have added new security features that prevent the exploit from working.

Writing on his twitter page, Rabet has warned fellow hackers to not update their 3DS system software to version 9.3. However, he suggested that some of the NINJHAX exploits still work.

Publishers and hardware manufacturers tend to clampdown on exploits that allow users to run unlicensed code, primarily due to fears that such hacks pave the way for piracy.