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Choosing an Environment

CFW on sysMMC vs. CFW on emuMMC

A "CFW Environment" describes the context in which you are using custom firmware (CFW). As a reminder, custom firmware is never permanently installed, and runs independently on top of the system firmware. This means that you never have to commit to where you want to use custom firmware.

Atmosphère temporarily patches the OS to enable customisations. You can choose what version of the OS it patches, each time you turn on your system. Each option has its own benefits and drawbacks.

  • For the purposes of this guide, the suffix -NAND and -MMC are interchangeable.

Generally, sys- refers to the physical storage chip inside of your Switch. It stands for "system".

Generally, emu- refers to a virtual version of the OS, running from a microSD card. It stands for "emulated".

For more information on terminology, please refer to the glossary.

You get to decide! Your choices are between using the internal storage or emulated storage. The following will go over the advantages and disadvantages of either decision.

sysCFW (CFW on sysMMC)

CFW on sysMMC has the following benefits:

  • Parity of system settings, save data, and titles between CFW usage and standard usage (no need to duplicate digital games)
  • Significantly lower microSD card storage requirements
  • Possibility of online play during CFW use
  • Fast console response time
  • Longer microSD card lifespan

The following drawbacks:

  • A brick risk for risky behaviors, especially for modchip users [info]
  • A Nintendo server ban risk for misbehavior [info]
  • No custom app installations on the HOME Menu (guaranteed ban)
  • No possibility of custom profile pictures (guaranteed ban)

If you prefer snappiness, online play, and a seamless transition between official features and custom features, you may consider using CFW on sysMMC. In this guide, sysMMC is assumed to be utilised for online play.

  • Enjoying CFW features such as custom sysmodules and homebrew apps
  • Dumping eShop games, saves, and encryption keys for preservation or installation on emuMMC or external Switch emulators
  • Restoring modified save data for many games
  • Custom fonts and home menu theming
  • Modifying and cheating in most offline games (and some online games; [info])

emuMMC CFW

CFW on emuMMC has the following benefits:

  • No risk of bans as long as emuMMC remains offline from Nintendo [info]
  • A safe area to test dangerous or risky mods and homebrew
  • No chance of bricking and losing console-unique information while using CFW

CFW on emuMMC has the following drawbacks:

  • Large microSD size requirement (32GB or 64GB will be reserved, depending on if you use an Switch OLED or not) This also means a minimum of 128GB is required (unless you are an advanced user and can resize the USER partition of your NAND)
  • Slower console response times
  • No official online play while in CFW
  • More microSD card wear over time
  • Doubled digital game storage requirements

And the following considerations:

No parity between sysMMC and emuMMC (Game installs, save data, and system settings will be separated when you boot between the two)

If you prefer foolproofing, and a separation between official features and custom features, you may consider using CFW on emuMMC. In this guide, emuMMC is assumed to be utilised for offline play.

  • Installing game cartridges
  • Restoring modified save data for any game
  • Modding and cheating in any game
  • Custom fonts and home menu theming
  • Downgrading titles to base versions, without mandatory updates
  • Enjoying CFW features such as custom sysmodules and homebrew apps

To proceed with CFW on sysMMC, click on the following button: Continue with the sysCFW path

To proceed with CFW on emuMMC, click on the following button: Continue with the emuMMC path

Modchip Instability

Modchips

Modchips directly infiltrate communication with the internal storage chip. Due to this, there are slight chances of NAND backups being tainted with corrupted data. If a bad backup is restored to sysNAND, the console can be bricked, and a modchip alone won't be able to fix it. To be safe, either only run an emuMMC on a console with a modchip, verify BOOT0/1 backups using tools like NXNandManager (Windows) or test NAND backups by running them as emuMMCs before you flash them to the sysNAND.