Useful Switch homebrew terminology

JIG

A jig is a simple device used to connect 2 pins on the right-hand controller rail. Which is needed to enter RCM on an unpatched console. It's usually simple 3D-printed plastic with a metal wire ().

OFW stands for Original Firmware. It is your device's unmodified firmware.

CFW Stands for Custom Firmware. It is a firmware that modifies the system firmware to allow it to run homebrew.

A term used to describe unofficial software created by developers for a locked-down system. When it comes to the Switch, such software can include save managers, emulators, or games.

A free and open source CFW created and maintained by SciresM and other contributors.
Technically a collection of patches and not a regular CFW. But it's easier to refer to it as a CFW.

Stands for embedded MMC. eMMC is your device's built-in memory. (not to be confused with emuMMC or the SD card).
The original Nintendo Switch has the memory size of 32GB and by default has 25.9GB of free storage, and the rest is taken up by the operating system.

sysMMC stands for "system MMC". The sysMMC is the contents stored on your device's built-in memory (not to be confused with OFW).
Referring to the internal storage as sysMMC instead of eMMC makes it clearer to differentiate from emuMMC. It contains the operating system itself, games and save files.
Every device, hacked or unhacked, has a sysMMC.

emuMMC stands for "emulated MMC". The emuMMC is created by copying your SysNAND and resides on your SD card and not on your device's internal memory.
Think of it as having a secondary Nintendo Switch on your SD card.
It is used to isolate any actions that you might perform from your sysMMC that could either harm your device or get you banned.
Any changes or actions that you perform in your emuMMC won't affect your sysMMC since it is just a copy and they are fully separate.
⚠️ Having an emuMMC on its own won't protect you from being banned. See the page about avoiding a console ban for more information on how to avoid being banned.

It's common to use NAND instead of MMC by people hacking Switch consoles. sysNAND instead of sysMMC/eMMC. emuNAND instead of emuMMC.
This guide will use sysMMC and emuMMC, as the Hekate and Atmosphère devs use emuMMC.

Signature patches or SigPatches allow your device to bypass signature checks performed by horizon for installed titles. This is used to allow the use of game backups.
A properly configured Hekate launch option and patches, or sys-patch is required for signature patching.

A custom bootloader that allows you to bypass fuse checks and has a lot of useful tools.
Can be used to boot into stock, Atmosphère (CFW) using emuMMC or sysMMC, Android, Linux, and any other payload.

A custom minimal bootloader that is only used to boot into Atmosphère.
The main difference between Hekate and Fusee is that Hekate needs a custom configuration file that tells Atmosphère what KIPs, patches and other settings it should use. While Fusee ~~boots them automatically~~ requires an additional sys-module to load them properly. (It used to load them automatically before version 1.7.0)

The Nintendo Switch uses the Tegra's fuse driver for accessing one time programmable data. Mainly referred to for their anti-downgrade use which does not affect users of the RCM exploit or modchip users.

Nintendo Submission Package or NSP is either a dump of an installed title (base game, update, dlc) or a homebrew package that can be installed.

An extension that homebrew applications use.
These homebrew .nro files are placed in the switch folder, or individual folders within the switch folder. And can be started from the homebrew menu.

Paid, no longer maintained and closed source CFW created by Team Xecuter.
The last release was for firmware 11.0.0.

When talking about a Switch ban, people are usually referring to the console losing the ability to use Nintendo's online features. Like the eShop (buying, downloading, updating), cloud saves and friends activity.
Bans are permanent. You can not get a Switch unbanned.