The only 100% legal method to acquire DSi BIOS files is to dump them directly from your own physical Nintendo DSi console. To do this, your console must be modified to run homebrew software. Prerequisites for Dumping Your Own BIOS A Nintendo DSi console. An SD card (formatted to FAT32).
The DSi is more than just a DS with two cameras. It has double the RAM, a faster processor (running at 134MHz), internal flash storage, and a full operating system. This DSi-enhanced hardware requires the dedicated DSi-mode BIOS files. These files unlock access to the console's increased memory, its cameras, and the unique DSiWare digital storefront. To run a DSi-enhanced game, such as Pokémon Black Version 2, in DSi mode, you need the DSi BIOS and NAND files; the standard DS BIOS files will relegate the game to legacy DS compatibility mode. dsi bios files download
The Nintendo DSi occupies a unique space in handheld gaming history. As a bridge between the wildly successful DS Lite and the 3D-capable Nintendo 3DS, the DSi introduced a dedicated digital store, built-in cameras, and enhanced internal hardware. Today, preserving and playing DSi-exclusive titles—as well as standard DS games with enhanced DSi features—requires a solid understanding of DSi emulation. The only 100% legal method to acquire DSi
You might come across downloadable "packs" on sites like the that claim to offer BIOS and NAND files. While it's true that these files exist online, please remember that downloading them, even from such a public resource, is legally no different from downloading a commercial game ROM. The files are still copyrighted, and downloading a dump created by someone else (even for a console you own) is generally not legal. The only way to be 100% certain you are operating within the law is to dump the files from your own hardware. An SD card (formatted to FAT32)