For support (in English) with GodMode9, as well as help with scripting and to get updates and info, join GodMode9 on Discord.
GodMode9 is a full access file browser for the Nintendo 3DS console, giving you access to your SD card, the FAT partitions inside your SysNAND and EmuNAND, and basically anything else. Among other functionality, you can copy, delete, rename files, and create folders.
Note that if you have any payload files other than GodMode9.firm in the /luma/payloads/ folder on your SD card, holding Start on boot will display a "chainloader menu" where you will have to use the D-Pad and the A button to select "GodMode9" for these instructions.
GodMode9 is powerful software that has the capability to modify essentially anything on your console. Though many of these modifications are locked behind a permissions system, and it is impossible to accidentally perform dangerous actions without deliberately unlocking permissions, you should still follow instructions carefully and keep backups just in case.
Updating GodMode9
Some of the instructions below are only applicable to the latest version of GodMode9, and as such you should follow this section to update your copy before continuing. Overwrite any existing files.
What You Need
The latest release of GodMode9 (the GodMode9 .zip file)
Instructions
Power off your device
Insert your SD card into your computer
Copy GodMode9.firm from the GodMode9 .zip to the /luma/payloads folder on your SD card
Copy the gm9 folder from the GodMode9 .zip to the root of your SD card
Reinsert your SD card into your device
GodMode9 is now up to date.
Creating a NAND Backup
Press and hold Start, and while holding Start, power on your device. This will launch GodMode9
Press Home to bring up the action menu
Select "Scripts..."
Select "GM9Megascript"
Select "Backup Options"
Select "SysNAND Backup"
Press A to confirm
This process will take some time
If you get an error, make sure that you have at least 1.3GB of free spaec on your SD card
Press A to continue
Press B to return to the main menu
Select "Exit"
Press A to relock write permissions if prompted
Hold R and press Start at while still holding R to power off your device
Your NAND backup has been successfully created. You can find it in /gm9/out/ under the name <date>_<serialnumber>_sysnand_###.bin, along with its accompanying checksum (.sha) file. You will probably want to back up these files to somewhere safe, then delete them from your SD card to reclaim the space.
Restoring a NAND backup
Power off your device
Insert your SD card into your computer
Copy <date>_<serialnumber>_sysnand_###.bin from your computer to the /gm9/out/ folder on your SD card
Reinsert your SD card into your device
Press and hold Start, and while holding Start, power on your device. This will launch GodMode9
Press Home to bring up the action menu
Select "Scripts..."
Select "GM9Megascript"
Select "Restore Options"
Select "SysNAND Restore (safe)"
Select your NAND backup
Press A to unlock SysNAND (lvl3) writing, then input the key combo given
This will not overwrite your boot9strap installation
This process will take some time
Press A to continue
Press B to return to the main menu
Select "Exit"
Press A to relock write permissions if prompted
Hold R and press Start at while still holding R to power off your device
Your NAND backup has been successfully restored. You can now delete <date>_<serialnumber>_sysnand_###.bin from your SD card.
Injecting any .CIA app into Health & Safety
Note that you cannot inject something that is larger than Health & Safety. You'll only be able to install inject relatively small homebrew (no retail games).
Press and hold Start, and while holding Start, power on your device. This will launch GodMode9
Navigate to the location of your .cia file
Press A on the .cia file to select it
Select "CIA image options..."
Select "Mount image to drive"
Press A on the .app file
Select "NCCH image options
Select "Inject to H&S"
Press A to unlock SysNAND (lvl1) writing, then input the key combo given
Press A to continue
Press A to relock write permissions if prompted
Your desired application has now been injected into Health & Safety.
Restoring Health & Safety after injecting a .CIA app
This will only work if you performed the initial injection with GodMode9. If you've been following this page, then you did it with GodMode9.
Press and hold Start, and while holding Start, power on your device. This will launch GodMode9
Press Home to bring up the action menu
Select "More..."
Select "Restore H&S"
Press A to unlock SysNAND (lvl1) writing, then input the key combo given
Press A to relock write permissions if prompted
Health & Safety has been reverted to normal.
Format an SD card
This will erase the contents of your SD card!
Press and hold Start, and while holding Start, power on your device. This will launch GodMode9
Press Home to bring up the action menu
Select "More..."
Select "SD format menu"
Select an EmuNAND option if you wish to use one
If you don't know what it is or have no legitimate use for it, select "No EmuNAND"
Select "Auto"
Press A to accept the label GM9SD
You can input a custom name if you want
When prompted, input the key combo given to confirm the format
Your SD card has successfully been formatted for use with the 3DS.
Removing an NNID without formatting your device
This process will only log you out of your NNID. You will still not be able to use the NNID on another console, as the NNID remains linked to the console.
Press and hold Start, and while holding Start, power on your device. This will launch GodMode9
Press Home to bring up the action menu
Select "Scripts..."
Select "GM9Megascript"
Select "Scripts from Plailect's Guide"
Select "Remove NNID"
Press A to continue
Press A to unlock SysNAND (lvl1) writing, then input the key combo given