What is fantasi?

Fantasi is custom firmware, meaning replacement software that runs directly on the hardware, for a handful of small pocket-sized devices used for radio and security tinkering. It supports the Flipper Zero, a device called Kiisu, the Chameleon Ultra, and the Proxmark3, with a couple more boards listed as coming soon. One codebase builds firmware for all of these different chips at once, along with a command line tool that runs on your computer to talk to whichever device you plug in. Building the project requires a C compiler for ARM chips and git, both of which need to be available on your system. Running a plain build command compiles firmware for every supported device plus the host command line tool in one go, or you can target just one platform. Two extra libraries, one for reading input and one for Bluetooth, are needed to build the full host tool. Once built, a flash command uploads the new firmware onto a connected device. If more than one device is plugged in, it refuses to guess which one to flash and asks you to specify. The tool is designed so that a failed or bad firmware upload cannot permanently break the device, since the original bootloader is always preserved. The host command line tool connects to a device over a USB cable or over Bluetooth and gives you a way to browse the device's file storage almost like a small computer, with commands to list files, move between folders, upload files, and delete things. Fantasi also supports small custom programs, called apps, that can be written and compiled separately, then loaded onto a device and run from its memory or its flash storage. The device itself understands commands for checking battery level, Bluetooth status, memory usage, and other diagnostics directly over a serial connection.