You can inject the Flipnote Studio ROM or download the official Flipnote Studio 3D variant (which allows you to view classic DSi flipnotes) via custom firmware like Luma3DS and FBI. Connecting to Custom Servers: Sudomemo
For the absolute best experience, installing Flipnote Studio on a softmodded DSi or 3DS gives you perfect stylus precision and camera integration. nintendo ds flipnote studio rom