This page lists possible causes and fixes of Luma3DS exception screens. They are not applicable to every situation, but cover most common known issues.
Reading a Luma3DS exception screen
A Luma3DS exception has four (or five, in a few cases) different parts to it that help in finding its cause, as follows:
Processor: What part of the system is causing the exception. The two processors are:
Arm9: The 'security processor' of the system. These exceptions usually result from errors in NAND data or hardware faults in either the 3DS or its SD card.
Arm11: The 'userland' of the system. These exceptions have numerous causes but are often related to broken software or user data.
Exception type: How the system is causing the exception. These categories are often too broad to be helpful, but three of them are more precise:
data abort: Oftentimes related to a broken mod or broken HOME Menu data. Occasionally related to custom firmware data being broken.
prefetch abort (svcBreak): Oftentimes an issue with data on the NAND, even when Arm11. Can also happen when launching an out-of-region game.
undefined instruction: Usually either a broken piece of software (if not on boot) or outdated boot.firm (if on boot).
Fault status: Why the system is causing the exception. Normally not helpful except for developers.
Current process: Where the error is coming from in the system. Often the most helpful part of the exception. Some examples of processes are as follows:
fs: The filesystem, i.e. either the SD card or the NAND.
menu: Data that is opened either as a part of the HOME Menu or at the same time as it.
loader: The service that opens apps, meaning the app you last tried to open has an issue.
nwm: Networking services, almost always WiFi.
R0: Usually just internal data that's not worth reading. There are two notable exceptions, however:
Arm11 loader exception: If R0's contents start with a C or D, R0 is an error code. This code usually gives the exact cause of the issue.
Arm11 pm exception: If R0's contents are E0E01BF5, boot.firm is guaranteed to be too outdated to work.
Known Errors
In the following lists, the file prefixes on file paths refer to the starting location. sdmc:/ refers to the SD card, and numbers in the format of [X:] refer to GodMode9's drive numbers.
If the below fixes do not solve your issue or you are unsure of what to do, join the [Nintendo Homebrew Discord] for further assistance.
Select which processor the error says it comes from.
The system movable, [1:]/private/movable.sed, is 288 bytes but a flag is enabled that expects a size of 320 bytes.
To fix, boot into GodMode9 and select SYSNAND CTRNAND, then go into the private folder. Inside this folder, you will see a file named movable.sed. Select it, and under the options menu, select Show in Hexeditor. Green-colored numbers will appear in the middle of the screen - press A and then unlock writing to sysNAND (lvl2). At the beginning of the file, look for the set of numbers 53 45 45 44 00 01. Once you find these numbers, hold A and press D-PAD DOWN while the 01 value is highlighted to change it to 00. Press B, then A, then B to save changes and exit from the hexeditor, then press START to reboot your console.
SYSNAND CTRNAND has bad CMACs.
To fix, press R+A on the SYSNAND CTRNAND drive and Fix CMACs for drive. The console will act like it has been formatted after this, and this is intended.
To fix, either perform a Safe Mode update, attempt to enter System Settings before the crash occurs and delete the application in Data Management, or reformat the SD card.
prefetch abort
An installation of menuhax is conflicting with the custom firmware.
To fix, place the menuhax67_installer.3dsx file from [this download] into sd:/3ds, run it through Homebrew Launcher, and choose REMOVE.
prefetch abort (svcBreak)
The f000000b folder in SYSNAND CTRNAND is broken, its exact location being at [1:]/data/<ID0>/extdata/00048000/f000000b.
To fix, backup f000000b by pressing R+A while highlighting it, then selecting Copy to 0:/gm9/out. Once it is backed up, delete the folder. If this does not fix the issue, copy the folder back where it was.
ns
prefetch abort (svcBreak)
The Luma configuration setting Autoboot Homebrew is set to boot to a title that does not exist.
To fix, disable the option or install an application that matches the title ID set in sd:/luma/config.ini.
nwm
any
The WiFi chipset's hardware is damaged or dead.
To fix, replace the WiFi chipset with a new one. To avoid the error until then, disable WiFi on the 3DS and do not turn it back on.
If the 3DS is an old model, you can disable WiFi with an external switch. New models must instead disable it through the HOME Menu Settings or Rosalina. Repeatedly pressing the keycombo for Rosalina while powering on might let you access Rosalina before it can crash.
pm
undefined instruction
The installed version of Luma3DS likely does not support the current firmware version. This is guaranteed to be true if the contents of R0 are E0E01BF5.
The app you last opened has an issue of some kind.
To fix, disable all game mods, cheat codes, and plugins to ensure they are not the cause.
If the error still happens, then the game itself is likely faulty. If it is a cartridge dump, redump it. If it is an eShop game, click the Repair button at the bottom of its eShop page or delete and reinstall it. If it is a cartridge, clean the cartridge and the 3DS cartridge reader with isopropyl alcohol.
CtrApp
any
Broken system software is interfering with the app you last opened.
To fix, disable all game mods, cheat codes, and plugins to ensure they are not the cause. If the error still happens, update from Safe Mode. If this does not work, perform a CTRTransfer.
GARDEN
any
Animal Crossing's game data or savedata is having issues.
To fix, disable all game mods, cheat codes, and plugins to ensure they are not the cause. If the error still happens, then the game itself may be faulty. If it is a cartridge dump, redump it. If it is an eShop game, click the Repair button at the bottom of its eShop page or delete and reinstall it. If it is a cartridge, clean the cartridge and the 3DS cartridge reader with isopropyl alcohol.
If the error yet still happens, ensure that you have not used a save editor before the error started happening. If it has been edited, you will need to restore a backup from before its use, or wipe the save and start over if you have no backup.
fs
any
Can be anything from SD card problems to hardware issues.
Kujira Joker niji_loc
any
The app you last opened has an issue of some kind.
To fix, disable all game mods, cheat codes, and plugins to ensure they are not the cause. If the error still happens, ensure the game is the same region as the console - if it is not, force the game to use the correct region.
If the error yet still happens, then the game itself is likely faulty. If it is a cartridge dump, redump it. If it is an eShop game, click the Repair button at the bottom of its eShop page or delete and reinstall it. If it is a cartridge, clean the cartridge and the 3DS cartridge reader with isopropyl alcohol.
loader
undefined instruction
The app you last opened has an issue. If the contents of R0 start with C or D, R0 is an error code.
Most of the possible error codes for this are also listed on this page (WIP).
mset
any
System Settings is broken in some way - this may indicate that the console has a hardware issue.
If neither of these work, the console has a serious issue. Join the [Nintendo Homebrew Discord] and ask, in English, for help.
nwm
any
The WiFi chipset's hardware is damaged or dead.
To fix, replace the WiFi chipset with a new one. To avoid the error until then, disable WiFi on the 3DS and do not turn it back on.
If the 3DS is an old model, you can disable WiFi with an external switch. New models must instead disable it through the HOME Menu Settings or Rosalina. Repeatedly pressing the keycombo for Rosalina while powering on might let you access Rosalina before it can crash.
qtm cam
any
The camera's hardware is damaged or dead.
To fix, replace the camera with a new one. To avoid the error until then, disconnect the camera or avoid using anything that activates the camera.
