This guide provides comprehensive information on Nintendo DSi firmware, including how to update to the latest official version and how to install custom firmware (CFW) for a much improved experience. What is the Latest Official Nintendo DSi Firmware?
Unlike the 3DS (which allowed system transfers), or the Wii (which allowed USB updates), the DSi was designed to update via one of two methods: Nintendo Dsi Firmware Download
Extract the contents of TWiLight Menu++ to the root of your SD card. Nintendo Dsi Firmware Download
The DSi becomes a truly portable homebrew console. Nintendo Dsi Firmware Download