My 3DS crashes on boot after installing a theme

This is fixable. The theme is probably corrupted. Try these steps:

1. Insert the SD card into your computer.
2. Open Nintendo 3DS/(32 Character ID)/extdata/00000000/.
3. Delete the folder for your region:
   • US: 000002cd
   • EU: 000002ce
   • JP: 000002cc
4. Ensure Anemone3DS is up-to-date.
5. Reinstall the theme or try another if the issue persists.