The steps detailed here generally assume that your console has a modern custom firmware setup (boot9strap + Luma3DS 8.0 or greater). If your console is running an older homebrew setup (for example, something based on arm9loaderhax or menuhax), you should update your setup before trying these instructions.

Power/notification light indicators

My console powers off when I try to turn it on, and/or the notification LED shows a color on boot

There is an issue with your boot.firm file. If you're running boot9strap 1.4, your 3DS notification LED may flash a certain color. This color is used to diagnose issues involving your boot.firm file on SD card or internal memory. On older versions of boot9strap, the blue light will power off almost immediately when trying to turn on the console.

If the notification LED flashes:

White: Your 3DS was not able to find boot.firm on your SD card or on internal memory.
Magenta: Your 3DS was not able to find boot.firm on your SD card. It was able to find boot.firm on internal memory, but the file is corrupted.
Red: Your 3DS was able to find boot.firm on both your SD card and on internal memory, but both files are corrupted.

You can get a new boot.firm file by downloading the latest release of Luma3DS, extracting it, and placing boot.firm on the root of your SD card. If your boot.firm file is consistently being detected as corrupted, you may want to check your SD card for errors. Also, note that the 3DS tends to have issues with files extracted using WinRAR.

If you hear a "popping sound", potentially accompanied with the backlight turning on for a split second, there is a hardware issue with your console (such as a disconnected backlight cable). You may be able to get your console to boot by holding it at certain angles.

My console gets stuck on a black screen with blue power light staying on

Follow the Black Screen Unbrick page

Error message on boot

An error has occurred: Failed to apply 1 FIRM patch(es)" or "An exception has occurred -- Current process: pm"

Your Luma3DS version is outdated. Download the latest release of Luma3DS and place boot.firm on the root of your SD card, replacing any existing file. Make sure you are extracting the ZIP file with any tool other than WinRAR, as it is known to cause issues with 3DS-related files.

Unable to mount CTRNAND or load the CTRNAND FIRM. Please use an external one."

There are a number of reasons as to why this could be happening. In any case, this error can usually be fixed by following the CTRTransfer guide.

"An error has occurred. Hold down the POWER button to turn off the power..."

ARM11 exception handlers are disabled, or custom firmware is not installed. Try enabling ARM11 exception handlers:

Power off your console
Hold (Select)
Power on your console, while still holding (Select)
If the "Disable ARM11 exception handlers" box is checked, uncheck it

HOME Menu is missing installed applications

This could be caused by various reasons, but most likely because your SD card is not being read by the system. You can check if your SD is being read by holding SELECT on boot and checking the yellow text on the bottom screen; if it says "Booted from CTRNAND via B9S", then your console is booting from the internal memory and not from the SD card. If this is the case, attempt the steps below, which are listed from easiest to hardest:

Power off your console, remove the SD card, re-insert it, then power on your console
Power off your console, remove the SD card, insert it on your computer, download the latest release of Luma3DS, extract boot.firm from the Luma3DS.zip and place it on the root of your SD card (replacing any existing file)
Power off your console, remove the SD card, insert it on your computer and reformat your SD (this will wipe your SD card data)
Test your SD card for errors by following the guide according to your computer's operating system: Checking SD card integrity. If your SD card is marked as faulty, then you will have to replace your SD card
Your SD card slot may be broken. Join Nintendo Homebrew on Discord for further assistance

Blue "BOOTROM ERROR" screen

Your console is likely hard-bricked. You will need to buy an ntrboot flashcart to reinstall boot9strap in order to attempt to fix your console. This may also indicate a hardware issue that cannot be fixed. In any case, join Nintendo Homebrew on Discord for assistance.

It is also possible that someone has set a boot-time splash screen that just looks like a brick. Try leaving your console powered on, waiting on the blue screen, for five minutes.

Some other error

Please take a photo of the error and join Nintendo Homebrew on Discord for assistance.

Software issues on consoles with custom firmware

DSi / DS functionality is broken or has been replaced with Flipnote Studio

Follow the DS mode unbrick guide

GBA Virtual Console and/or Safe Mode functionality is broken

Your console is running Luma3DS 6.6 or older, likely via arm9loaderhax. You should follow A9LH to B9S to update your console to a modern custom firmware environment.

Extended memory mode games (Pokemon Sun/Moon, Smash, etc.) don't work

This can occur after a CTRTransfer or region change on Old 3DS / 2DS. This is most likely fixed by following Section VI - Delete system config savedata of the CTRTransfer guide.

Exception screen when booting/loading an application

Look for your exception screen in this page. If you weren't able to find your error or the instructions didn't work, join Nintendo Homebrew on Discord for further assistance.

Opening the HOME Menu settings crashes the console or loads the Homebrew Launcher

Your console likely still has menuhax67 installed. To uninstall menuhax67 follow removing menuhax67

Other troubleshooting

Unable to update console

The steps below can be attempted in any order, but are listed from easiest to hardest to perform.

If you are using Pretendo, switch to Nintendo Network with Nimbus
Set your DNS settings to Auto
Move closer to your WiFi router
Update from Safe Mode by turning off the console, holding L+R+D-Pad Up+A on boot, and following the on-screen prompts
Delete your WiFi connection, then reconnect to your WiFi again
Reboot your WiFi router
Connect to a different WiFi connection, like a mobile hotspot
Nintendo servers may be down; Try again later
If you still get an error, follow CTRTransfer, then try again
For further support (in English), join Nintendo Homebrew on Discord

Clear HOME Menu extdata

Power off your console
Insert your SD card into your computer
Navigate to the /Nintendo 3DS/<ID0>/<ID1>/extdata/00000000/ folder on your SD card
Delete the corresponding folder for your 3DS region:
- EUR Region: 00000098
- JPN Region: 00000082
- USA Region: 0000008f
- CHN Region: 000000A1
- KOR Region: 000000A9
- TWN Region: 000000B1
Reinsert your SD card into your console

Clear HOME Menu theme data

Power off your console
Insert your SD card into your computer
Navigate to the /Nintendo 3DS/<ID0>/<ID1>/extdata/00000000/ folder on your SD card
Delete the corresponding folder for your 3DS region:
- EUR Region: 000002ce
- JPN Region: 000002cc
- USA Region: 000002cd
Reinsert your SD card into your console

Multiple ID0

If you have multiple long 32-character folders (ID0) inside your Nintendo 3DS folder, follow this guide.

Multiple ID1

If you have multiple long 32-character folders (ID1) inside your ID0, follow this guide.

Manually entering Homebrew Launcher

Follow the guide to manually enter the Homebrew Launcher.

Turning off Parental Controls

Follow the guide to remove Parental Controls.

Broken NVRAM

Follow the guide to fix NVRAM.

Unable to complete initial console setup

Follow the guide to skip initial setup.