Software information: RaspberryPi: Beta RPi ROM

The beta RPi ROM – available from the downloads page – provides the latest beta ROM image (a file ‘riscos/img’) for the Raspberry Pi.

This software is suitable for models of Raspberry Pi up to and including the Pi 3A+, 3B+ and Compute Module 3+.

It will load on the Raspberry Pi 4, but some hardware features are non-functional – see Raspberry Pi 4 port status for details.

Please note that the beta ROM is untested, work-in-progress software. Some components may be unfinished and/or contain serious bugs: that is what development is about! You should only use the beta ROM if you are willing to accept the risks involved and have a suitable backup strategy in place.

If you are new to RISC OS you may prefer to download one of the “stable release” images instead (e.g. the RISC OS Pi SD image, which contains all the necessary elements ready to be copied to a blank SD card).

Installing the beta ROM on a Pi 1, Pi 2 or Pi 3

The ROM image can be used as a direct replacement for your existing RISC OS ROM image.

You should also download the “Nightly Beta HardDisc4” image from the Miscellaneous downloads page, as that contains the latest development version of !Boot.

Please note that RISC OS 5.27 cannot use the Raspberry Pi firmware files (bootcode.bin, fixup.dat and start.elf) supplied with earlier releases of RISC OS. Instructions on how to obtain updated firmware can be found at Software information: Raspberry Pi: Firmware.

Full step-by-step instructions for performing the upgrade can be found here.

Using the beta ROM on a Pi 4

If you are already using RISC OS 5.27 on an earlier model of Raspberry Pi, that build will require the following modifications to support the Pi 4:

• This ROM image as a direct replacement for the existing RISC OS ROM image
• Additional firmware, as mentioned on Software information: Raspberry Pi: Firmware
• A 3-line modification to config.txt – see config.txt (Raspberry Pi) for details
• To correct a screen brightness bug, ensure that cmdline.txt contains “disable_gamma” on its first line.

See Raspberry Pi 4 port status for more information (including hardware restrictions).

Further information

For more on bootloader files (including config.txt and cmdline.txt) see Software information: Raspberry Pi: Firmware.

You may also wish to read Using RISC OS on the Raspberry Pi.

An explanation of how the Raspberry Pi port works is also available.