I see a lot of users are facing issues with Atmosphere 2001-0123. Honestly, nobody likes a crash screen with code especially if it is a boot crash. The Nintendo Switch consoles running custom firmware (CFW) such as Atmosphere or Hekate are known for their boot crash. The steps below address this issue and it involve deleting the error code or making a NAND backup, generating certain files, and performing a system wipe.

Quick solution for Atmosphere 2001-0123

Quick solution for Atmosphere 2001-0123

Method one

This method has proven effective for many users.

  • Step 1: Go to your SD card and navigate to atmosphere/contents folder
  • Step 2: Locate and delete the error code as seen on the crash information. The most frequently seen error code is 420000000007E51A, 100000000081, and 010000000000001F but yours can have a different error code

When you do this, no need for an MMC rebuild and If this method doesn’t work (it should work), proceed to Method 2 with caution.


Method two

Boot Crashes

  1. If booting via Atmosphere/Hekate, and the TitleID/ProgramID is in Atmosphere/contents delete it
  2. Check if you can boot normally
    • If you can, your cfw setup is corrupt
  3. Perform a System Wipe

MMC Rebuild

Step 1: Making a nand backup

You probably want to make a nand backup before you start modifying your switch. Boot into Hekate, Go to tools, Backup eMMC, and backup both eMMC BOOT0 & BOOT1 and eMMC RAW GPP

Step 2: Getting the files

What you need:

  • Your own prod.keys file (This needs to be yours specifically (Unless you are trying to just generate the BIS files)! If you don’t have them, try to dump them via Lockpick_RCM)
  • Your switch firmware (Try to dump them via Tegraexplorer if you don’t have them)
  • EmmcHaccGen


  1. Extract the EmmcHaccGen zip somewhere, and place the prod.keys and the fw dump in the same folder
  2. Open up a cmd prompt in the same folder, and execute the command EmmcHaccGen.exe --keys (location of the prod.keys file) --fw (location of the firmware folder) (example: EmmcHaccGen --keys prod.keys --fw 9.1.0))
  3. You should now have a folder called NX-(fw version)_exFAT. If you do, you can continue

Step 3: Flashing the files

What you need:


  1. Make a folder on your sd card, then copy boot.bis, SYSTEM and systemrestore.te in that folder
  2. Insert your sd card in your switch and inject Tegraexplorer.bin
  3. Navigate to SD, your folder, systemRestore.te and then Launch Script
  4. Follow the script til completion (Restore both BIS and SYSTEM)
  5. Try to boot your switch with Atmosphere.
    • Note: if you followed the entirety of this guide, AutoRCM will be enabled! You need to boot via RCM
    • If you do not have a basic Atmosphere setup on your SD, Download the atmosphere zip and fusee-primary.bin from here. Extract the contents of the zip to the root of your sd, and inject fusee-primary.bin
    • If your switch does not boot, perform the System Wipe

System Wipe

System Wipe

This will wipe everything from your system. Including saves, installed games and everything else. Be safe and always have a nand backup

What you need:


  1. Inject TegraExplorer using your favorite payload injector (for example TegraRcmGui)
  2. Select SystemWipe.te from the main menu
  3. Select Wipe sysmmc to wipe sys
  4. Confirm using power

Method two source: https://suchmememanyskill.github.io/guides/unbrick/#mmc-rebuild


It’s essential to proceed with caution when making changes to your Nintendo Switch system files, as improper modifications can potentially lead to more significant issues. If you’re not comfortable with these steps, consider seeking help from a knowledgeable friend or a community that specializes in Nintendo Switch homebrew.

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