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3DS:Error screens/Luma3DS exception screen: Difference between revisions

Guide to the CFW error handler
m (add error for autoboot homebrew fail)
(complete overhaul of the entire page, plus almost a dozen new errors)
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{{shortcut|3DS:EXC}}
This page lists possible causes and fixes of Luma3DS exception screens. They are not applicable to every situation, but cover most common known issues.
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==
==Reading a Luma3DS exception screen==
Line 11: Line 12:
**'''undefined instruction''': Usually either a broken piece of software (if not on boot) or outdated <code>boot.firm</code> (if on boot).  
**'''undefined instruction''': Usually either a broken piece of software (if not on boot) or outdated <code>boot.firm</code> (if on boot).  
*'''Fault status:''' Why the system is causing the exception. Normally not helpful except for developers.
*'''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. Common or unique processes are as follows:
*'''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''': Files on your SD card or NAND are having issues.
**'''fs''': The filesystem, i.e. either the SD card or the NAND.
**'''hid''': Potential hardware problems.
**'''menu''': Data/extdata that is opened either as a part of the HOME Menu or at the same time as it.
**'''menu''': Some of the data/extdata that's either associated with the HOME Menu or loaded at the same time is broken.
**'''loader''': The service that opens apps, meaning the app you last tried to open has an issue.
**'''pm''': Almost always, <code>boot.firm</code> is too outdated to work.
**'''nwm''': Networking services, almost always WiFi.
**'''loader''': The app you last tried to run has an error.
**'''qtm'''/'''cam''': Your camera has a hardware issue.
**'''nwm''': Your WiFi chip is damaged, dying, or entirely dead. This always means you must disable WiFi to stop the errors.
*'''R0''': Usually just internal data that's not worth reading. There are two notable exceptions, however:  
*'''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 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.
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==Known Errors==
==Known Errors==
Note that the prefixes on file paths refer to the starting location. <code>sdmc:/</code> refers to the SD card, and numbers in the format of <code>[X:]</code> refer to GodMode9's drive numbers.
In the following lists, the file prefixes on file paths refer to the starting location. <code>sdmc:/</code> refers to the SD card, and numbers in the format of <code>[X:]</code> refer to GodMode9's drive numbers.
{{info|If the below fixes do not solve your issue or you are unsure of what to do, join the [[https://discord.gg/nintendohomebrew Nintendo Homebrew Discord]] for further assistance.}}
{{info|If the below fixes do not solve your issue or you are unsure of what to do, join the [[https://discord.gg/nintendohomebrew Nintendo Homebrew Discord]] for further assistance.}}
===Arm9===
----
Select which processor the error says it comes from.
<tabber>
|-|Arm9=


====On boot====
<span style="font-size:175%; display:flex; justify-content:center">Error On Boot</span>
*Files on the SD are corrupted.
{| class="wikitable" style="margin: auto"
**To fix, [[Checking_SD_card_integrity|verify that your card is not faulty.]] If it is verified working, make a backup of all intact files, [[Formatting_an_SD_card|format the SD card]], and try booting again.
! style="font-size:125%;" | Exception Type
*A system save located on the NAND in <code>[1:]/data</code> has a problem.
! style="font-size:125%;" | Problem & Solution
*System-unique files are missing from the NAND in <code>[1:]/rw/sys</code>.
|-
| rowspan="3" | Any
| Files on the SD are corrupted.  
:To fix, [[Checking_SD_card_integrity|verify that your card is not faulty.]] If it is verified working, make a backup of all intact files, [[Formatting_an_SD_card|format the SD card]], and try booting again.
|-
| A system save located on the NAND in <code>[1:]/data</code> has a problem.
|-
| System-unique files are missing from the NAND in <code>[1:]/rw/sys</code>.
|-
| rowspan="2" | data abort
| The <code>shared2</code> folder in <code>[2:] SYSNAND TWLN</code> is missing.
:To fix, create this folder.
|-
| System titles have been deleted.
To fix, perform a [[3DS:Safe Mode|Safe Mode update]].<br>If this does not work, perform a [[3DS:CTRTransfer|CTRTransfer]].
|-
| rowspan="2" | prefetch abort (svcBreak)
| The system movable, <code>[1:]/private/movable.sed</code>, is 288 bytes but its flag indicates otherwise.
|-
| <code>SYSNAND CTRNAND</code> has bad CMACs.
:To fix, press R+A on the <code>SYSNAND CTRNAND</code> drive and <code>Fix CMACs for drive</code>. Your system will act like it has been formatted after this, and this is intended.
|-
| prefetch abort (kernel panic)
| Your console likely has a hardware issue.
|}


=====Prefetch abort (svcBreak)=====
<span style="font-size:175%; display:flex; justify-content:center">Error During Use</span>
*The system's movable, <code>[1:]/private/movable.sed</code>, is 288 bytes but its flag indicates otherwise.
{| class="wikitable" style="margin: auto" 
*<code>SYSNAND CTRNAND</code> has bad CMACs.
! style="font-size:125%;" | Exception Type
**To fix, press R+A on the <code>SYSNAND CTRNAND</code> drive and <code>Fix CMACs for drive</code>. Your system will act like it has been formatted after this, and this is intended.
! style="font-size:125%;" | Problem & Solution
|-
| data abort
|Files on the SD are corrupted.  
:To fix, [[Checking_SD_card_integrity|verify that your card is not faulty.]] If it is verified working, make a backup of all intact files, [[Formatting_an_SD_card|format the SD card]], and try again.
|}


=====Data abort=====
|-|Arm11=
*<code>SYSNAND TWLN</code>'s <code>[2:]/shared2</code> folder is missing.
**To fix, create this folder.
*System titles have been deleted.
**To fix, perform a [[3DS:Safe Mode|Safe Mode update]]. If this does not work, perform a [[3DS:CTRTransfer|CTRTransfer]].


====During use====
<span style="font-size:175%; display:flex; justify-content:center">Error On Boot</span>
*Files on the SD are corrupted.  
{| class="wikitable" style="margin: auto"
**To fix, [[Checking_SD_card_integrity|verify that your card is not faulty.]] If it is verified working, make a backup of all intact files, [[Formatting_an_SD_card|format the SD card]], and try again.
! style="font-size:125%;" | Current Process
! style="font-size:125%;" | Exception Type
! style="font-size:125%;" | Problem & Solution
|-
| boss || data abort
| The current firmware version is too old for SpotPass to work. Perform a [[3DS:Safe Mode|Safe Mode update]].
:If this does not work, you may require [[3DS:CTRTransfer|a CTRTransfer.]]
|-
| fs || any
| Can be anything from SD card problems to hardware issues.
|-
| hid || any
| Potential hardware problems.
|-
| ic2, spi || any
| Your 3DS has a serious hardware issue that likely is not easily fixable.
:Join [https://discord.gg/C29hYvh the Nintendo Homebrew Discord] and ask, in English, for help.
|-
|-
| mset || any
| System Settings is broken in some way - this may indicate that your console has a hardware issue.
:To fix, perform a [[3DS:CTRTransfer|CTRTransfer]], or a [[3DS:CTRTransfer/Manual|Manual CTRTransfer]] if that does not work.
::If neither of these work, your system has a serious issue. Join [https://discord.gg/C29hYvh the Nintendo Homebrew Discord] and ask, in English, for help.
|-
| rowspan="5" | menu
| rowspan="3" | data abort
| Broken HOME Menu theme.
:To fix, go into the folder <code>sd:/Nintendo 3DS/<ID0>/<ID1>/extdata/00000000/</code> and delete the folder matching your region, one of the following:
::USA: <code>000002cd</code><br>EUR: <code>000002ce</code><br>JPN: <code>000002cc</code>
|-
| Broken HOME Menu extra data.
:To fix, go into the folder <code>sd:/Nintendo 3DS/<ID0>/<ID1>/extdata/00000000/</code> and delete the folder matching your region, one of the following:
::USA: <code>0000008f</code><br>EUR: <code>00000098</code><br>JPN: <code>00000082</code><br>KOR: <code>000000A9</code>
|-
| Broken HOME Menu application.
:To fix, either perform a [[3DS:Safe Mode|Safe Mode update]], attempt to enter System Settings before the crash occurs and delete the application in Data Management, or [[Formatting an SD card|reformat the SD card]].
|-
| prefetch abort
| An installation of menuhax is conflicting with your custom firmware.
:To fix, place the <code>menuhax67_installer.3dsx</code> file from [[https://github.com/zoogie/menuhax67/releases/download/v1.1/menuhax67_v1.1.zip this download]] into <code>sd:/3ds</code>, run it through Homebrew Launcher, and choose REMOVE.
|-
| prefetch abort (svcBreak)
| The <code>f000000b</code> folder in <code>SYSNAND CTRNAND</code> is broken, its exact location being at <code>[1:]/data/<ID0>/extdata/00048000/f000000b</code>.
:To fix, backup <code>f000000b</code> by pressing R+A while highlighting it, then selecting <code>Copy to 0:/gm9/out</code>. 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 [[3DS:Luma3DS/Configuration|Luma configuration]] setting <code>Autoboot Homebrew</code> 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 <code>sd:/luma/config.ini</code>.
|-
| nwm || any
| The WiFi chip is damaged or dead.
:To fix, replace the WiFi chip with a new one - to avoid the error or if you cannot obtain a new WiFi chip, disable WiFi on the 3DS.
::Old models can disable WiFi via an external switch, but new models have to disable it through the HOME Menu Settings.
|-
| pm || undefined instruction
| Your installed version of Luma3DS likely does not support the current firmware version. This is guaranteed to be true if the contents of R0 are <code>E0E01BF5</code>.
:To fix, [[3dsguide:restoring-updating-cfw|update CFW.]]
|-
|}


===Arm11===
<span style="font-size:175%; display:flex; justify-content:center">Error During Use</span>
 
{| class="wikitable" style="margin: auto"
====On boot====
! style="font-size:125%;" | Current Process
 
! style="font-size:125%;" | Exception Type
=====boss (0004013000003402), data abort=====
! style="font-size:125%;" | Problem & Solution
*The current firmware version is too old for SpotPass to work.  
|-
**To fix, perform a [[3DS:Safe Mode|Safe Mode update]]. If this does not work, you may require [[3DS:CTRTransfer|a CTRTransfer.]]
| 3dsx_app || any
 
| The <code>.3dsx</code> file you tried to open is corrupted.
=====fs (0000000000000000)=====
:To fix, download a new copy of the <code>.3dsx</code> file. If this error happens when you open the Homebrew Launcher, download a new copy of <code>boot.3dsx</code>.
*Can be anything from SD card problems to hardware issues.
::If the error still happens, [[Checking SD card integrity|test your SD for errors.]]
 
|-
=====hid (0004013000001D02)=====
| app || any
*Potential hardware problems.
| 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.
=====ns (0004013000008002), prefetch abort (svcBreak)=====
::If the error still happens, then the game itself is likely faulty. If it is a [[3DS:Dump titles and game cartridges#Dumping a Game Cartridge|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.
*The [[3DS:Luma3DS/Configuration|Luma configuration]] setting <code>Autoboot Homebrew</code> 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 <code>sd:/luma/config.ini</code>.
| CtrApp || any
 
| Broken system software is interfering with the app you last opened.
=====menu (000400300000__02), data abort=====
:To fix, disable all game mods, cheat codes, and plugins to ensure they are not the cause. If the error still happens, [[3DS:Safe Mode|update from Safe Mode]]. If this does not work, [[3DS:CTRTransfer|perform a CTRTransfer]].
*Broken HOME Menu theme.
|-
**To fix, go into the folder <code>sdmc:/Nintendo 3DS/<ID0>/<ID1>/extdata/00000000/</code> and delete the folder matching your region, one of the following:
| fs || any
***USA: <code>000002cd</code>
| Can be anything from SD card problems to hardware issues.
***EUR: <code>000002ce</code>
|-
***JPN: <code>000002cc</code>
| Kujira, Joker || any
*Broken HOME Menu extra data.
| The app you last opened has an issue of some kind.
**To fix, go into the folder <code>sdmc:/Nintendo 3DS/<ID0>/<ID1>/extdata/00000000/</code> and delete the folder matching your region, one of the following:
:To fix, disable all game mods, cheat codes, and plugins to ensure they are not the cause. If the error still happens, ensure your game is the same region as your console - if it is not, [[3DS:SGL|force the game to use the correct region.]]
***USA: <code>0000008f</code>
::If the error yet still happens, then the game itself is likely faulty. If it is a [[3DS:Dump titles and game cartridges#Dumping a Game Cartridge|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.
***EUR: <code>00000098</code>
|-
***JPN: <code>00000082</code>
| loader || undefined instruction
***KOR: <code>000000A9</code>
| The app you last loaded has an issue. If the contents of R0 start with C or D, R0 is an error code.<br>
*Broken HOME Menu application.
Most of the possible error codes are present on [[3DS:Error_screens/Luma3DS_ErrDisp|this page]], but the most common ones for this are as follows:
**To fix, perform a [[3DS:Safe Mode|Safe Mode update]].  
:<code>C8804478</code>/<code>C80044AB</code>: A file or app that is supposed to exist was not found.<br><code>D900458B</code>/<code>D9004587</code>: The app you opened has corrupted data, savedata, or update(s). If it is a [[3DS:Dump titles and game cartridges#Dumping a Game Cartridge|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 this does not fix it, attempt to enter System Settings before the crash occurs and find the broken application in Data Management, if possible.  
|-
**If ''this'' does not fix it, you may try to enter GodMode9 and use its title list to find the broken application - this is risky, however, and should not be attempted without guidance unless you know exactly what you are doing. For guidance, join the [[https://discord.gg/nintendohomebrew Nintendo Homebrew Discord]].
| mset || any
 
| System Settings is broken in some way - this may indicate that your console has a hardware issue.
======menu (000400300000__02), prefetch abort======
:To fix, perform a [[3DS:CTRTransfer|CTRTransfer]], or a [[3DS:CTRTransfer/Manual|Manual CTRTransfer]] if that does not work.
*An installation of menuhax is conflicting with your custom firmware.  
::If neither of these work, your system has a serious issue.  
**To fix, place the <code>menuhax67_installer.3dsx</code> file from [[https://github.com/zoogie/menuhax67/releases/download/v1.1/menuhax67_v1.1.zip this download]] into <code>sdmc:/3ds</code>, run it through Homebrew Launcher, and choose REMOVE.
| nwm || any
 
| The WiFi chip is damaged or dead.
======menu (000400300000__02), prefetch abort (svcBreak)======
:To fix, replace the WiFi chip with a new one - to avoid the error or if you cannot obtain a new WiFi chip, disable WiFi on the 3DS.
*The f000000b folder in <code>SYSNAND CTRNAND</code> is broken, its exact location being at <code>[1:]/data/<ID0>/extdata/00048000/f000000b</code>.
::Old models can disable WiFi via an external switch, but new models have to disable it through the HOME Menu Settings.
**To fix, backup that folder by pressing R+A while highlighting it, then select <code>Copy to 0:/gm9/out</code>. Once backed up, delete the folder. If this does not fix the issue, copy the folder back where it was.
|-
 
| qtm, cam || any
=====pm (0000000000000000), undefined instruction=====
| The camera is damaged or dead.
*The installed version of Luma3DS does not support the current firmware version.
:To fix, replace the camera with a new one - to avoid the error until you can replace it, do not use anything that turns on the camera.
**To fix, [[3dsguide:restoring-updating-cfw|update CFW.]]
|-
 
|}
 
</tabber>
====During use====
 
=====loader (0000000000000000)=====
If the hexadecimal number next to R0 starts with 'C' or 'D', search for it as an error code or in [[3DS:Error_screens/Luma3DS_ErrDisp]].<br>
These errors are usually due to corruption, such as a faulty/dirty SD card or game cartridge.


[[Category:Unbricking]]
[[Category:Unbricking]]
{{Short description|Guide to the CFW error handler}}

Revision as of 06:14, 3 March 2023

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:

Luma3DS exception.png
  • 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.
    • 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/extdata 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.

OOjs UI icon information-progressive.svg 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.

Error On Boot

Exception Type Problem & Solution
Any Files on the SD are corrupted.
To fix, verify that your card is not faulty. If it is verified working, make a backup of all intact files, format the SD card, and try booting again.
A system save located on the NAND in [1:]/data has a problem.
System-unique files are missing from the NAND in [1:]/rw/sys.
data abort The shared2 folder in [2:] SYSNAND TWLN is missing.
To fix, create this folder.
System titles have been deleted.

To fix, perform a Safe Mode update.
If this does not work, perform a CTRTransfer.

prefetch abort (svcBreak) The system movable, [1:]/private/movable.sed, is 288 bytes but its flag indicates otherwise.
SYSNAND CTRNAND has bad CMACs.
To fix, press R+A on the SYSNAND CTRNAND drive and Fix CMACs for drive. Your system will act like it has been formatted after this, and this is intended.
prefetch abort (kernel panic) Your console likely has a hardware issue.

Error During Use

Exception Type Problem & Solution
data abort Files on the SD are corrupted.
To fix, verify that your card is not faulty. If it is verified working, make a backup of all intact files, format the SD card, and try again.

Error On Boot

Current Process Exception Type Problem & Solution
boss data abort The current firmware version is too old for SpotPass to work. Perform a Safe Mode update.
If this does not work, you may require a CTRTransfer.
fs any Can be anything from SD card problems to hardware issues.
hid any Potential hardware problems.
ic2, spi any Your 3DS has a serious hardware issue that likely is not easily fixable.
Join the Nintendo Homebrew Discord and ask, in English, for help.
mset any System Settings is broken in some way - this may indicate that your console has a hardware issue.
To fix, perform a CTRTransfer, or a Manual CTRTransfer if that does not work.
If neither of these work, your system has a serious issue. Join the Nintendo Homebrew Discord and ask, in English, for help.
menu data abort Broken HOME Menu theme.
To fix, go into the folder sd:/Nintendo 3DS/<ID0>/<ID1>/extdata/00000000/ and delete the folder matching your region, one of the following:
USA: 000002cd
EUR: 000002ce
JPN: 000002cc
Broken HOME Menu extra data.
To fix, go into the folder sd:/Nintendo 3DS/<ID0>/<ID1>/extdata/00000000/ and delete the folder matching your region, one of the following:
USA: 0000008f
EUR: 00000098
JPN: 00000082
KOR: 000000A9
Broken HOME Menu application.
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 your 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 chip is damaged or dead.
To fix, replace the WiFi chip with a new one - to avoid the error or if you cannot obtain a new WiFi chip, disable WiFi on the 3DS.
Old models can disable WiFi via an external switch, but new models have to disable it through the HOME Menu Settings.
pm undefined instruction Your 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.
To fix, update CFW.

Error During Use

Current Process Exception Type Problem & Solution
3dsx_app any The .3dsx file you tried to open is corrupted.
To fix, download a new copy of the .3dsx file. If this error happens when you open the Homebrew Launcher, download a new copy of boot.3dsx.
If the error still happens, test your SD for errors.
app 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, 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.
fs any Can be anything from SD card problems to hardware issues.
Kujira, Joker 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 your game is the same region as your 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 loaded has an issue. If the contents of R0 start with C or D, R0 is an error code.

Most of the possible error codes are present on this page, but the most common ones for this are as follows:

C8804478/C80044AB: A file or app that is supposed to exist was not found.
D900458B/D9004587: The app you opened has corrupted data, savedata, or update(s). 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.
mset any System Settings is broken in some way - this may indicate that your console has a hardware issue.
To fix, perform a CTRTransfer, or a Manual CTRTransfer if that does not work.
If neither of these work, your system has a serious issue.
nwm any The WiFi chip is damaged or dead.
To fix, replace the WiFi chip with a new one - to avoid the error or if you cannot obtain a new WiFi chip, disable WiFi on the 3DS.
Old models can disable WiFi via an external switch, but new models have to disable it through the HOME Menu Settings.
qtm, cam any The camera is damaged or dead.
To fix, replace the camera with a new one - to avoid the error until you can replace it, do not use anything that turns on the camera.