If you have Luma3DS custom firmware installed, download the latest GodMode9.zip . Extract the luma folder and gm9 folder to the root of your SD card. Also copy the GodMode9.firm to /luma/payloads/ and rename it to x_GodMode9.firm (the x makes it boot by holding Start).
You can only restore a NAND backup that came from your specific console. Restoring a foreign NAND (one you downloaded online) will change your encryption seed and permanently brick your 3DS. 3ds nand download install
A 1GB backup file kept on your Google Drive is cheap insurance. A lost 3DS due to a failed hack is a tragedy. Go make your backup now . If you have Luma3DS custom firmware installed, download
A: Do it immediately after installing custom firmware. Do it again before any major system update (e.g., 11.15 to 11.16). Do it after you finish setting up all your apps. You can only restore a NAND backup that