The Nintendo 3DS was a handheld gaming console released in 2011.

Like many other gaming consoles, you can only run software that is approved by the manufacturer on it. To run your own software ("homebrew"), one has to exploit flaws in the OS and use them to remove these restrictions. One side effect of homebrew is that it often leads to piracy of approved software.

One of the most common step-by-step guides that help users install homebrew uses an exploit called Bannerbomb3 to run the installer. [0] By inserting a malformed DSiWare application onto the SD card, the System Settings app can be crashed in such a way that facilitates arbitrary code execution. The loaded program is then used to install custom firmware.

In March 2023, Nintendo shut down the eShop, the digital software storefront for the Nintendo 3DS, effectively ending most support for the console. After this happened, many people started advocating homebrew-ing 3DSes to allow pirated software to be installed on them, since purchasing software digitally could no longer be done.

Now, 2 months later, Nintendo has decided to issue a firmware update that patches the Bannerbomb3 exploit, preventing new 3DS systems from being homebrewed in this fashion if they are on the latest firmware. (It should be noted that there are many, many more exploits for the 3DS [1], so I'm not sure why they've decided to fix this exact one.)

[0] https://3ds.hacks.guide

[1] https://www.3dbrew.org/wiki/Homebrew_Exploits

The 3DS is the Nintendo handheld that followed the DS. It has a very robust homebrew scene due to having a passionate community and not so good security. Homebrew allowed for a ton of new features including surprisingly strong emulation, customizing system menus, running your own code, patching of other games at runtime for modding/translating, etc. Obviously it also opened the door to piracy which makes it something Nintendo is eager to shut down. 3DS hit EoL a while ago (users can no longer make legitimate purchases through Nintendo), yet despite months having gone by since then Nintendo has decided to go back and patch up one of the more convenient methods for enabling homebrew which is something that is considered a dick move since they weren't making money off of it anymore anyways and even if they were it is YOUR SYSTEM and you should be able to do what you want with it. Fortunately there are unpatchable zero-day exploits for the system but they are not as easy as the one that Nintendo patched.

Homebrew on Nintendo consoles has always had a really interesting scene but it really took off with the Wii and everything after it. Hackers would keep finding ways to get into everything and Nintendo would hastily patch it up in a sort of live cat and mouse game. The exploit that Nintendo patched just recently is not hard to do, but older exploits were even easier. One of the earlier 3DS exploits was to simply drop a modified audio file onto your SD card and play it in the 3DS audio player. You would own the whole device in ten seconds flat.