- Extract your save with a homebrew (JK's Save Manager or other)
- Open savedataArc.txt, edit
- Re-import your save with a homebrew (JK's Save Manager or other)
- Edit your island
- Edit Mii ( Name, Last name, level, experience, and other)
- Edit global things (concerts hall songs, reset Miis apartment, unlock all items...)
https://github.com/Brionjv/Tomodachi-Life-Save-Editor/releases
https://gbatemp.net/threads/wip-tomodachi-life-save-editor.399006/