Atmosphère is a work-in-progress customized firmware for the Nintendo Switch.

Stratosphère (Custom Sysmodule(s)) - In Progress

For user's benefits, we'll likely want custom sysmodules -- both of the Rosalina style to extend the kernel/provide new features, and of the loader re-implementation style to hook important system actions.

Troposphère (Application-level Horizon OS patches) - In Progress

Patches will need to be developed for Horizon to implement desirable CFW features.

Thermosphère (EL2 Emunand support) - In Progress

In the absence of a released coldboot entrypoint, Atmosphère will want to support backing up and using virtualized/redirected NAND images.

Exosphère (Customized TrustZone) - In Progress

Atmosphère will want to run a customized Secure Monitor.

Fusée (First-stage Loader) - In Progress

Atmosphère will need a loader -- this will be responsible for loading and validating stage 2 (custom TrustZone) plus package2 (Kernel/FIRM sysmodules), and patching them as needed. (This should implement all functionality normally in Package1loader/NX Bootloader).

Credits

Atmosphère is currently being developed and maintained by SciresM, TuxSH, and hexkyz.
In no particular order, we credit the following for their invaluable contributions:

• switchbrew for the libnx project and the extensive documentation, research and tool development pertaining to the Nintendo Switch.
• devkitPro for the devkitA64 toolchain and libnx support.
• ReSwitched Team for additional documentation, research and tool development pertaining to the Nintendo Switch.
• ChaN for the FatFs module.
• Riley for suggesting "Atmosphere" as a Horizon OS reimplementation+customization project name.
• naehrwert for the hekate project and its hwinit code base.
• hedgeberg for research and hardware testing.
• lioncash for code cleanup and general improvements.
• jaames for designing and providing Atmosphère's graphical resources.
• Everyone who submitted entries for Atmosphère's splash design contest.
• All those who actively contribute to the Atmosphère repository.