Raspberry Pi: RISC OS boot-up issues (Rev #1)

Introduction

This page details some of the problems you may experience when trying to boot-up RISC OS for the first time on a Raspberry Pi.

The suggestions given here assume that a recent “RISC OS Pi” image is being used, either downloaded from this site or installed via Raspberry Pi Imager.

Blank screen (or Pi “rainbow” screen)

On older models of Raspberry Pi (Pi Zero, Pi 1, Pi 2, Pi 3) boot-up can get stuck at a completely blank screen, or at a “rainbow” screen with no text.

The Activity LED may be flashing a distinct pattern (a number of short flashes followed by a number of long flashes). For what these mean, see LED warning flash codes.

• The most likely problem is the SD card itself. Check it is seated correctly, check that the contacts in the card slot aren’t damaged in any way, clean it all up, and try again.

• If the LED warning flash code indicates a problem with a firmware file (and cleaning the contacts on the SD card/slot hasn’t worked) you can try updating the firmware as detailed below.

You should not see the “rainbow” screen on a Pi 4B or Pi 400: you should instead see the boot diagnostics screen (see next item).

Pi 4 “boot diagnostics” screen appears

On a Raspberry Pi 4B, boot-up may stop at the Raspberry Pi “boot diagnostics” screen, with a message similar to “Boot loader software is too old – upgrade boot loader”.

This is because the versions of start4.elf and fixup4.dat distributed with RISC OS 5.28 are too old for the latest hardware revisions of the Raspberry Pi 4B.

The fix is to download and install the latest versions of start4.elf and fixup4.dat – see detailed instructions below.

Boot-up stops at “Contacting DHCP server”

Pi Zero / Pi A+ / Pi 3A+

These models do not have an Ethernet interface, and RISC OS does not yet support WiFi.

You can still boot into RISC OS by disabling networking:

1. Press ESC to reach the desktop (click Cancel on the dialogue box that appears).
2. Now click the middle mouse button on the Task Manager icon (the Raspberry Pi icon at the bottom right corner of the screen) and choose “Configure…” from the menu.
3. In the Configuration window, click on “Network” followed by “Internet”.
4. Untick the box labelled “Enable TCP/IP Protocol Suite”.
5. Close the Internet configuration window and click “Save” on the Network configuration window. You will be prompted to reboot: this should boot to the desktop with networking disabled.

Pi 4B / Pi 400

RISC OS does not yet support the latest hardware revisions of the Pi 4B and Pi 400. The Ethernet chip on these devices will not function, and RISC OS does not yet support WiFi.

You can still boot into RISC OS by disabling networking, as described for the Pi Zero above.

Boot-up issues not mentioned here

If you encounter a boot-up issue not listed here, your first port of call should be the Community support forum.

Downloading new firmware

Some of the fixes require the Raspberry Pi firmware to be updated.

The recommended download procedure for a Pi 4B or Pi 400 is:

• Go to the Raspberry Pi firmware download site on GitHub
• Click on “boot”.
• Click on “fixup4.dat”
• Click on the Download button.
• Click on your browser’s BACK button.
• Click on “start4.elf”.
• Click on the Download button.

The recommended download procedure for a Pi Zero, Pi 1, Pi 2 or or Pi 3 is:

• Go to the Raspberry Pi firmware download site on GitHub
• Click on “boot”.
• Click on “bootcode.bin”
• Click on the Download button.
• Click on your browser’s BACK button.
• Click on “fixup.dat”
• Click on the Download button.
• Click on your browser’s BACK button.
• Click on “start.elf”.
• Click on the Download button.

To install the new firmware:

• Insert the RISC OS SD card into a SD card reader connected to another machine (Windows/Mac/Linux).
• Open a window on the first (or only) partition on the card. This is usually labelled “Boot” and will contain files with names such as config.txt, fixup.dat, fixup4.dat, riscos.img, start.elf and start4.elf.
• For a Pi 4B or Pi 400, delete the files “fixup4.dat” and “start4.elf”, replacing them with the new versions you downloaded above.
• For a Pi Zero, Pi 1, Pi 2 or Pi 3, delete the files “bootcode.bin”, “fixup.dat” and “start.elf”, replacing them with the new versions you downloaded above.
• Dismount the card (on macOS this option is labelled “Eject”) and wait for its icon to disappear. You may instead get a message of the form “It is now safe to disconnect the device”.
• Unplug the SD card from the card reader and reinsert the SD card into the Pi.