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The instructions given below are suitable for all models of Raspberry Pi up to and including the Pi 4.
Support for the Raspberry Pi 4 is a work in progress: see Raspberry Pi 4 port status? for more information.
The Pi 1, Pi 2 and Pi 3 use the following files:
bootcode.bin
– The boot loader for the CPU.start.elf
– The GPU firmware. Forms a matched pair with fixup.datfixup.dat
– Additional code for the GPU. Forms a matched pair with start.elfriscos.img
– The RISC OS ROMconfig.txt
– Configuration parameters for the boot loader. See below for suggested contents.cmdline.txt
– (Optional) Additional parameters to be passed to the kernel (i.e. RISC OS). See below for possible contents.On the Pi 4, the following two files take the place of bootcode.bin
, start.elf
and fixup.dat
:
start4.elf
– The Pi 4 GPU firmware. Forms a matched pair with fixup4.datfixup4.dat
– Additional code for the Pi 4 GPU. Forms a matched pair with start4.elfNote that the Pi4 has its boot code in the onboard EEPROM so it does not need bootcode.bin.
If you install bootcode.bin
, start.elf
and fixup.dat
alongside start4.elf
and fixup4.dat
, the card will boot on older models of Raspberry Pi as well as the Pi 4.
If you have the latest 5.27 ROM, there is a good chance that the latest Raspberry Pi firmware will work. Visit the Raspberry Pi firmware download site on GitHub to download the latest versions of bootcode.bin, start.elf and fixup.dat.
If you experience problems with the latest firmware – or if your RISC OS ROM dates from 2019 or earlier1 – you should try an older firmware release:
The procedure to follow is:
1 A Raspberry Pi firmware change in June 2019 means that older RISC OS ROMs cannot use the latest firmware.
2 A RISC OS code change in January 2019 means that RISC OS 5.27 cannot use the firmware supplied with earlier RISC OS distributions.
Use a recent build of RISC OS 5.27 (15 (13 March September 2020 or later) and recent firmware (February ( 2020 or later). For the 8GB model, use firmware dated May 2020 or later.June 2020 or later).
There are two firmware files to download: start4.elf and fixup4.dat.
The procedure to follow is:
This is a plain text file. The following example should be suitable for all models of Raspberry Pi, including the Pi 4:
[pi4]
enable_gic=1
[all]
fake_vsync_isr=1
framebuffer_swap=0
gpu_mem=64
init_emmc_clock=100000000
ramfsfile=CMOS
ramfsaddr=0x508000
kernel=RISCOS.IMG
Parameters specific to the Pi 4 appear in the “pi4” section of the file; parameters applicable to all models of Raspberry Pi appear in the “all” section.
These parameters – and several others that may be of interest to RISC OS users – are discussed in more detail at config.txt (Raspberry Pi).
This file is optional: RISC OS will still boot if it is not present.
If you are running RISC OS 5.27 you may need to specify the following parameter to avoid a blank screen issue.
disable_gamma
Parameters must be space separated on the first line of the file, so if you wanted to specify two parameters you would do it like this:
disable_mode_changes disable_gamma
For details of the parameters available, see cmdline.txt (Raspberry Pi).