Fusée

Fusée is the bootloader, and is split into two parts.

This is due to the way CFW booted currently, namely the Tegra X1 RCM vulnerability, also known as Fusée Gelée. This only allows a payload of limited size to be send to the device.

Fusée replaces Nintendo's Package1loader/bootloader.

Fusée-Primary

Fusée-Primary is the initial payload to be send to a Tegra X1 RCM vulnerable Switch.

The RCM payload (fusee-primary.bin) is limited in size. The solution is to first push a smaller payload which then prepares the device and loads the second stage, Fusée-Secondary, from the SD.

For configuration it reads the BCT.ini file from SD.

Fusée-Secondary

Fusée-Secondary (fusee-secondary.bin) is responsible for preparing the Switch hardware for later running environments.

It contains multiple Modules(kip's) that modify existing or bring new features to the OS. Additionaly Fusée-Secondary also validates and loads Exosphère.

Fusée is also capable of chainloading other environments including Linux and many more.