Delete me: Upgrading your Raspberry Pi to RISC OS 5.27 (Rev #3, changes)
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Introduction
This page details the process for upgrading an already-working RISC OS installation on a Raspberry Pi to RISC OS 5.27.
If you are upgrading from a recent (2017 or later) release, you can skip ahead to Please notehere.: If you are using an older (2016 or earlier) release, you will have to follow the whole process.RISC OS 5.27 is a development release that contains 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 RISC OS 5.27 if you are willing to accept the risks involved and have a suitable backup strategy in place.
Having said that, many builds of RISC OS 5.27 do work well. It may simply be a matter of trying a few different daily builds until you find one that meets your needs.
Prerequisites
Upgrading from releases earlier than RC15
At a minimum, you will need to download the following software:
This will be a two stage process. First you need to upgrade to RISC OS 5.24, then once you have 5.24 working you can upgrade to 5.27. Do not try to upgrade direct to RISC OS 5.27 – it may not work.
- The Beta ROM image from the Raspberry Pi downloads page.
- The Beta HardDisc4 image from the Miscellaneous downloads page.
- Updated Raspberry Pi firmware suitable for RISC OS 5.27.
- Download the stable ROM image and the stable HardDisc4 image.
A certain level of RISC OS knowledge is assumed, including how to use the command line, how to use the !Configure application and how to edit text files.
- Go to the RISC OS Upgrade page and follow the section titled Procedure for upgrading from RISC OS 5.19 or earlier.1 Don’t change the OS ROM just yet.
Once you have confirmed that !Boot still works properly, proceed as follows:
- Issue the command:
*SaveCMOS !Boot.Loader.CMOS
This saves your current CMOS settings in a place where the Pi bootloader can find them.
- Add the following lines to “CONFIG/TXT” inside !Boot.Loader:
ramfsfile=CMOSramfsaddr=0x508000
This instructs the Pi bootloader to load the CMOS file ready for use by RISC OS 5.24.
- Replace the RISCOS/IMG file (inside !Boot.Loader) with the RISC OS 5.24 ROM image.
- Reboot.
- If you were upgrading from RC10 or earlier, RISC OS will be using your CMOS settings but none of your old saved CMOS files will work. Save a new backup of your CMOS settings to somewhere safe:
*SaveCMOS $.Backups.CMOS-RO524(or a location of your own choosing)
- Once you have RISC OS 5.24 working to your satisfaction (we suggest you try it out for a week or two) you can upgrade to 5.27 as described in the next section.
1 The InSituBootUpgrade file (supplied with the 5.24 HardDisc4 image) assumes you are upgrading from 5.22, but RC14 was based on RISC OS 5.21 – to successfully use the InSituBootUpgrade process you’d need to run the 5.22 InSituBootUpgrade file first (and finding a copy of the 5.22 HardDisc4 image can be tricky). If you are upgrading from RISC OS 5.19 (Pi releases up to approximately RC10) you cannot use the InSituBootUpgrade process at all.
What release are you upgrading from?
The exact procedure to follow depends on the release of RISC OS you are currently running. Choose the appropriate entry from this list:
- RISC OS 5.24, 5.25 or 5.26
- RISC OS 5.23 (RC15)
- RISC OS 5.21 (RC11, RC12, RC12a, RC14)
- RISC OS 5.19 (RC10 or earlier)
Upgrading Disc from upgrades RC15, and 5.24, monitor 5.25 settings or 5.26
This should be a simple matter of checking your monitor configuration is appropriate for use at RISC OS 5.27, and then performing the upgrade itself. These two items are described in turn below.
Starting with releases prior to RISC OS 5.24
Monitor settings
These releases – with the possible exception of RC151 – are too old to retain the existing !Boot as it stands, so you will have to build a new !Boot directory based on the 5.27 version of !Boot. The process is as follows:
In earlier releases of RISC OS 5, the monitor pixel resolution chosen at boot-up time was controlled by two settings supplied to the Raspberry Pi bootloader (the “hdmi_group” and “hdmi_mode” lines in config.txt). If you want RISC OS to continue using those settings, you should add disable_mode_changes to cmdline.txt2. Otherwise, those settings will be ignored from RISC OS 5.24 onwards.
- Go to the RISC OS Upgrade page and follow the section titled Procedure for upgrading from RISC OS 5.19 or earlier2 to rebuild !Boot and upgrade the disc-based applications – use the Beta HardDisc4 image, not the “stable” image mentioned on the page. DON’T upgrade the OS ROM just yet.
Instead Once you have confirmed that !Boot – and the other applications in the Beta HardDisc4 image – still work properly, go toRISCMonitor configuration checks OS below. can now useEDID to obtain the native pixel resolution directly from the monitor itself. Most monitors manufactured in the last 15 years support EDID, so you should use it if at all possible.
2 1 For With example, RC15 you it may is be theoretically using possible a to display download the 5.24 stable disc image and run the “InSituBootUpdate” file inside that only archive supports – a specific pixel resolution, or perhaps you want might then be able to use go to the “AnyMode” utility.RISC OS 5.24 section on this page to complete the upgrade. This is completely untested with RC15 and you would do so at your own risk.
2 Avoiding a rebuild of !Boot with older releases is, at best, difficult. For builds based on 5.21 (i.e. Pi releases RC11 to RC14) you would need to run the InSituBootUpdate supplied with the 5.22 HardDisc4 image followed by the InSituBootUpdate supplied with the 5.24 HardDisc4 image (and finding a copy of the 5.22 HardDisc4 image can be rather tricky). If you are upgrading from RISC OS 5.19 (Pi releases up to RC10) you cannot use the InSituBootUpdate process at all.
Starting with RISC OS 5.24 or later
- Use the “Boot merge” facility (!Configure > Boot > Install) to install the new version of !Boot from the Beta HardDisc4 image. Reboot and fix anything that’s broken.3
- Replace all the ordinary applications (i.e. the contents of every directory except !Boot) from the Beta HardDisc4 image. Simply delete the old application of the same name (e.g. !Maestro) and copy the new application across.
3 “Boot Merge” saves all replaced files in the !Boot.Backup directory – this will allow you to retrieve any changes you may have made to !Boot components (e.g. amendments to a built-in monitor definition file) if they have been overwritten.
Monitor configuration checks
MonitorType and WimpMode
Two AtRISC OS 5.27, two CMOS RAM configuration settings – previously “MonitorType” all and but “WimpMode” ignored – are must now expected to hold valid information. These Releases are up “MonitorType” to and “WimpMode”: whileRISC OS 5.24 5.26 is are rather forgiving of unusual values in these two fields, but fromRISC OS 5.27 they must be correct or the monitor may not display a picture.must be correct or the monitor may not display a picture.
So, To it is necessary to check that the values settings: are correct before upgrading to 5.27.
- Open a Task window (ctrl-F12) and enter the following two commands:
*Status MonitorType*Status WimpMode
- If the MonitorType is set to a number between 0 and 8, you
MonitorTypeis set a number between 0 and 8, youmust change it:*Configure MonitorType Auto
If the monitor type is “Auto” or “EDID” you do not need to change it.
- If the WimpMode is set to a number, you must change it:
*Configure WimpMode Auto
You should now be ready to perform the upgrade to RISC OS 5.27.
The upgrade process itself
“disable_mode_changes” (Optional setting)
- First, download a Beta ROM image. You won’t be using it just yet, but it’s best to have a few ROM images of different dates, just in case a serious bug was accidentally introduced in a daily build.
In early releases of RISC OS 5 for the Raspberry Pi, the monitor pixel resolution chosen at boot-up was controlled by two settings supplied to the Raspberry Pi bootloader (the “hdmi_group” and “hdmi_mode” lines in config.txt).
- Next, download the Beta HardDisc4 image and upgrade the necessary components in !Boot (e.g. using the “System merge” facility in !Configure). Reboot and fix anything that’s broken.
From RISC OS 5.24 onwards, RISC OS will by default select a monitor pixel resolution according to the settings chosen in the “Screen” section of the !Configure application, thus ignoring the “hdmi_group” and “hdmi_mode” settings.
- Now, replace all the ordinary applications present in the beta HardDisc4 image: simply delete the old ones of the same name and copy the new ones across.
If you want RISC OS to continue using the “hdmi_group” and “hdmi_mode” settings4 you should add disable_mode_changes to CMDLINE/TXT inside !Boot.Loader. If the file doesn’t exist, create it.
- We recommend you continue using this setup for a week or two, so as to flush out any lurking problems before you upgrade the ROM.
4 For example, you may be using a display that only supports a specific pixel resolution, or perhaps you want to use the “AnyMode” utility.
- During this time it’s a good idea to grab a few more beta ROM images of different dates3. You should also check the Bugs and Community Support forums in case there are any problems with recent daily builds.
- You will also need to obtain updated Raspberry Pi firmware before you can install the ROM.
- If you have an old version of the ZeroPain module, delete it (it’s usually installed as !Boot.Choices.Boot.Predesk.!!ZeroPain). Recent versions of RISC OS will run happily without ZeroPain.4
- Create a text file called
CMDLINE/TXTinside !Boot.Loader (if it doesn’t already exist). The file should contain the textdisable_gammaon the first line. See cmdline.txt (Raspberry Pi) for details.
- Finally, install the Beta ROM (RISCOS/IMG) and updated firmware (BOOTCODE/BIN, START/ELF, FIXUP/DAT) into !Boot.Loader and reboot. This completes the upgrade.
3 The build date is mentioned immediately below the download link itself. Although listed as “daily” builds, they do occasionally skip a day or three.
4 If you want to continue using ZeroPain, the Beta ROM archive contains the latest version. Installation instructions are included in the archive.
Restart to check new monitor settings
- If you have changed any of the monitor settings, shut down and restart the machine.
- After the restart, you may find that the RISC OS desktop is displayed at a lower resolution than usual. To correct this, use the !Configure application to select a screen resolution more to your liking. For example, to use the monitor’s EDID settings, choose a monitor type of “Auto(your-monitor-name-here)” (e.g. “Auto(L225W)”) and a resolution of “Native”.5
5 If the menu option says “Auto(Unidentified)” it means that EDID has not worked. In this instance you should choose another monitor type from the list.
Upgrading the RISC OS ROM
We recommend you continue using your updated !Boot for a week or two, so as to flush out any lurking problems before you upgrade the ROM. This gives you time to grab a selection of Beta ROM images of different dates6 – just in case a serious bug was accidentally introduced in a daily build. You should also check the Bugs and Community Support forums to see if there are any problems with recent daily builds.
6 The build date is mentioned immediately below the download link itself. Although listed as daily builds, the average build frequency is closer to “once every 3-4 days”.
Preparing for the upgrade
- Edit the file called
CMDLINE/TXTinside !Boot.Loader (if it doesn’t already exist, create it) so that the textdisable_gammaappears on the first line of the file.
For example, if the file already contains “disable_mode_changes”, you would edit the first line to read:disable_mode_changes disable_gamma
- Check that !Boot.Loader contains a file called “CMOS”. If it doesn’t exist, use the *SaveCMOS command to create it:
*SaveCMOS !Boot.Loader.CMOS
- Check that “CONFIG/TXT” (inside !Boot.Loader) contains – at minimum – the following lines:
fake_vsync_isr=1framebuffer_swap=0gpu_mem=64init_emmc_clock=100000000ramfsfile=CMOSramfsaddr=0x508000kernel=RISCOS.IMG
If any lines are missing – particularly “ramfsfile” and “ramfsaddr” – you should add them. Do not remove any entries at this stage.
- Copy the existing versions of RISCOS/IMG, BOOTCODE/BIN, START/ELF and FIXUP/DAT from !Boot.Loader to another location, in case you need to regress to the old ROM version.
Installing the 5.27 ROM
- Install the updated firmware (BOOTCODE/BIN, START/ELF, FIXUP/DAT) into !Boot.Loader.
- Install the Beta ROM (RISCOS/IMG) into !Boot.Loader.
- Reboot.
After rebooting on RISC OS 5.27
- Go to !Boot.Choices.Boot.Predesk and delete the !!ZeroPain directory (if present). If you want to continue using ZeroPain, install the latest version from the Beta ROM archive. Note that RISC OS 5.27 will run happily without ZeroPain.
- Make a backup copy of your CMOS settings (either via “CMOS > Save” under !Configure, or by using *SaveCMOS) as some of the settings may have changed during the upgrade.7
- If you have upgraded from RC14 or earlier, you may want to edit CONFIG/TXT to remove any no-longer-needed entries (e.g. “hdmi_group” and “hdmi_mode” are only needed if you’re running AnyMode).
7 If you have upgraded from RC10 or earlier, none of your old “saved CMOS” files will work at RISC OS 5.27, so you will need a fresh backup anyway.
Common problems with the upgrade
- The mouse pointer is visible but the rest of the screen is black (either on boot or when selecting a 256-colour screen mode)
You upgraded the ROM but didn’t upgrade the firmware (bootcode.bin, start.elf, fixup.dat).
- Monitor doesn’t display a picture on boot
EITHER: You didn’t set MonitorType and WimpMode to “Auto”,
OR: you didn’t put “disable_gamma” on the first line of cmdline.txt.
SelectingDesktop is displayed at a256-colourlowerscreenresolutionmodethanproducesusualablackscreen(withthemousepointerstillvisible)YouUseupgraded“Configure > Screen” to change the monitor settings. To useROMEDIDbutchoosedidn’taupgrademonitorthetypefirmwareof(bootcode.bin,“Auto(start.elf,fixup.dat).your-monitor-name-here)” (e.g. “Auto(L225W)”) and a resolution of “Native”.
- Configuration changes don’t survive a reboot
(1) CONFIG/TXT (inside !Boot.Loader) may be missing the lines that load the CMOS file on boot. Check that the following lines are present:ramfsfile=CMOSramfsaddr=0x508000
(2) The CMOS file (inside !Boot.Loader) is missing/corrupted/read-only, or you have another file called CMOS in the root directory of the Filecore partition. Delete any wayward file(s), then issue:*SaveCMOS !Boot.Loader.CMOS
- Unexpected behaviour in applications after installing the 5.27 ROM
This can happen if you installed the ROM without upgrading !Bootaswell(or perhaps the attempted upgrade of !Boot didn’t go as well as you had hoped). Alternatively, there may be a serious bug in the specificROM build youchosechose,(inin which case you should replace theROM with another 5.27 daily build to see if that is anybetter).better.
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