DowngradeFixer

DowngradeFixer is a streamlined bare-metal payload designed to fix issues encountered when downgrading Nintendo Switch firmware from 21.0.0 to 20.5.0. It performs two critical operations without booting into Horizon OS.

Based on Lockpick_RCM_Pro by sthetix Originally based on Lockpick_RCMaster by THZoria

What It Does

DowngradeFixer automates two essential steps needed after downgrading your Nintendo Switch firmware:

1. Dumps prod.keys - Extracts encryption keys required for various homebrew tools
2. Deletes file 8000000000000073 - Removes the problematic save file from the SYSTEM partition that can cause issues after downgrading

Usage

1. Download the zip file in the release page, extract it to the sd card

2. Launch Hekate, click Payloads, then select DowngradeFixer.bin

3. Select "Fix Downgrade" from the main menu, then choose:

   • Fix SysNAND only - Process only the system NAND
   • Fix EmuNAND only - Process only the emulated NAND (if available)
   • Fix Both - Process both SysNAND and EmuNAND

4. The payload will silently:

   • Derive encryption keys and save prod.keys to /switch/prod.keys
   • Use those keys to access the encrypted SYSTEM partition
   • Delete the file 8000000000000073 from the SYSTEM/save partition
   • Display the results for each step

5. Reboot using one of the menu options:

   • Reboot to Hekate - Boots bootloader/update.bin if present
   • Power off - Safely powers down the console

Features

• Automated Fix - Performs both key dumping and file deletion in one operation
• Silent Key Derivation - Keys are derived and saved without verbose output
• Flexible NAND Selection - Choose to fix SysNAND, EmuNAND, or both
• Safe Operation - Validates each step and reports status
• No Horizon OS Required - Runs as a bare-metal payload for maximum compatibility
• Multiple Reboot Options - Launch Hekate, custom payload, or power off

When to Use This

Use DowngradeFixer when:

• You've downgraded your Nintendo Switch firmware from higher firmware e.g.22.1.0 to 20.5.0

Building

1. Install devkitARM.
2. Run:

   make release
   

Important Notes

• Backup First: Always keep backups of your NAND and important files
• One Purpose: This tool is specifically designed for the downgrade fix process
• Clean Operation: Only performs the two essential operations - no extras

License

DowngradeFixer is licensed under the GPLv2. The save processing module is adapted from hactool, licensed under ISC.

Credits and Attribution

This project is a streamlined version built upon:

• sthetix - Lockpick_RCM_Pro
• THZoria - Lockpick_RCMaster base
• shchmue - Original Lockpick_RCM
• CTCaer - Hekate bootloader and libraries
• Atmosphere-NX - Falcon keygen
• ReSwitched community - Development support

Disclaimer

This tool is for educational and legitimate backup purposes only. The authors are not responsible for any damage or data loss. Use at your own risk.

Support My Work

If you find this project useful, please consider supporting me by buying me a coffee!