This is an image of a RISC OS boot SD for the Raspberry Pi 400, suitable for writing to a real SD card using a utility such as dd (macOS/Linux) Win32DiskImager (Windows) or CloneDisc (RISC OS).
A microSD card of at least 2GB capacity is required. If you use a larger SD card (8GB, 16GB etc.) only the first 2GB will be usable by RISC OS.
This software is specially tailored for the Raspberry Pi 400. For other models of Raspberry Pi, please use the RISC OS Pi download instead.
To download this software, visit the Downloads page and click on RISC OS Pi 400.
In addition to the standard HardDisc4 contents, the RISC OS Pi image also includes:
Applications
Diversions
Documents
Programming
Utilities
Other (included in !Boot)
If you are new to RISC OS you should first read Introduction to RISC OS.
You may also want to read Using RISC OS on the Raspberry Pi.