Creating and Using EmuNAND

What is an EmuNAND?

An EmuNAND (Emualated NAND) is a copy of the Switch's SysNAND (System NAND) firmware that runs on the Switch's SD card, rather than it's internal eMMC storage. This is essentially a second switch OS that is a clean slate or a copy of your original firmware. You can use your sysNAND for homebrew, game dumping, online play, and playing retail games, whilst your emuNAND can be used to run custom user pictures, playing game backups, downgrading games down to the base release version, and using cheats in any game without fear of getting banned by Nintendo, since a properly set up emuNAND will be blocked from accessing online services, thus your original firmware on the internal storage of your Switch will be untouched from any game backups that have been installed on the EmuNAND. It can be stored on either a dedicated partition of the SD Card, or a file-based emuMMC where the contents of the NAND are accessed from a folder (though this method is less stable) and can be booted from either Fusee (Atmopshere's official bootloader), or the Hekate bootloader.

This guide assumes you have already formatted your SD Card on your Switch and you don't have Android or Linux installed

Items Needed

A Nintendo Switch that can access the Hekate Bootloader
An SD Card exceeding 32 GB formatted in exFAT or FAT32 (64 GB if you are using a Switch OLED, but more is HIGHLY recommended)
A Computer with USB Capabilities
- Optionally, a MicroSD to USB adapter to plug into a PC

Accessing Hekate

View the Installing Custom Firmware (CFW) guide for more information. If you came to this page from that page, then follow along.

Backing up the SysNAND

Using the touch screen (or left Joy-con analog stick), tap Tools, then Backup eMMC, then eMMC BOOT0 & BOOT1. After that backup is complete, select eMMC RAW GPP to back up the rest of the NAND. This will save the NAND backup to the SD card (file path shown on the Hekate backup screen). If your SD card is too small, you can also mount the NAND over USB and copy it directly to a PC with NxNandManger.
After your NAND backup, make sure to copy the folder it's located in to a safe location on a computer, phone, NAS, cloud storage, etc. Then, make sure to delete the NAND backup from the Switch in order to have more SD card space.

Creating EmuNAND

Once your NAND backup is safe, you are now ready to back up any installed games or other files on the SD card (if they exist) and reformat the card to have an emuMMC partition.

Navigate to Tools ⇒ Partition SD Card and drag the emuMMC to the right, until it says 29 GB FULL on a non-OLED model, or 58 GB FULL on an OLED model. You can also adjust sizes for Android/Linux partitions if you wish to install them later.
After adjusting your partition sizes, you can choose to manually back up your SD card's files by selecting the SD UMS button, and connecting it to a computer to copy the card's files to it. If you have less than 1 GB of data or just don't have any files you care about backing up, proceed to the next step.
- Do note that Hekate will automatically back up the SD card's files before a format/repartition if it has less than 1 GB of data. If you have more than 1 GB of data you would like to back up, then make sure to do it beforehand.
Tap the Next Step button. Make sure to understand the following prompt's warning and accept it. Hekate will now begin formatting and repartitioning the card.
After the format has completed, you can also restore any SD card files you had backed up previously. Go to USB Tools, then click SD card to connect the SD card to your computer through the Switch's USB port. Then, restore your desired files/folders.
Go to the Hekate home menu, and click the emuMMC button. You will now want to press the SD Partition button, and then create it on Part 0. The creation will take some time.
Once it is done, you can now reload Hekate. emuMMC can now automatically be accessed with Fusee, or with a hekate_ipl.ini launch option.