The DSLinux project has successfully brought the Linux operating system to the Nintendo DS and DS Lite, with potential compatibility for newer models. Surprisingly, DSLinux also runs on some NDS emulators. This functional system offers a wide range of useful Linux programs and boasts excellent documentation. However, it is worth noting that there are currently no active developers working on the project. Nevertheless, new contributors are encouraged to take up the mantle and utilize the available resources, including the comprehensive documentation found in the wiki.
https://www.dslinux.org/