What Can You Do by Modding a Nintendo DSi?

Modding a Nintendo DSi lets you run unlicensed homebrew software and expand what the system can do beyond its official firmware. According to the DSi Guide, homebrew runs for free on all DSi consoles regardless of firmware version or region; you only need an entry point (the guide's main one is Memory Pit) and an SD card. The guide also notes that the only brick risk comes from installing Unlaunch, and that risk is minimal.

Run DS and DSi game backups without a flashcard

You can play Nintendo DS(i) game backups or ROM hacks directly from the DSi SD card, with no flashcard required. This is one of the main practical reasons to mod the system, since it removes the need for a separate cartridge-based device.

Launch DSiWare from the SD card

Modding lets you launch any DSiWare title from your SD card. Because the software runs from the card rather than the system's region-locked store, out-of-region and 3DS-exclusive DSiWare also work.

Boot straight into apps with button combos

You can set the system to boot into DSiWare and homebrew applications by holding specific buttons when you turn the DSi on. This skips the normal menu and takes you directly to what you want to run.

Use emulators and homebrew games

The DSi can run various emulators for older classics, as well as custom homebrew games. These are unlicensed applications made for closed systems like the DSi, ranging from utilities to full games.

Play media and display a custom boot splash

Two media players are available: FastVideoDSPlayer and tuna-viDS. Note that FastVideoDSEncoder, used to prepare video for FastVideoDSPlayer, requires a CPU supporting AVX2 (newer CPUs will likely support it). You can also display a custom image, called a boot splash, on system launch.

Redirect NAND to the SD card with hiyaCFW

Using hiyaCFW, you can redirect your NAND to the SD card. This changes where the system reads its internal data from and is one of the more advanced options the guide covers.

Use normally incompatible flashcards

Modding also lets you run flashcards that would normally be incompatible with the system.

Where to find homebrew

The guide points to two sources:

What to know before starting

• On Windows, the guide recommends showing file extensions if you use the default File Explorer.
• Read all introductory pages of the guide before proceeding.
• The only brick risk comes from installing Unlaunch, and that risk is minimal.

If you want to go further, the guide's next step is its Get Started section, which walks through the modding process from the beginning.