PicoChess v4 Trixie Desktop Image [ 27 Feb 2026 ]

[RandyR]

Hi Everyone,

I have updated the v4 Desktop image for those who do not want to build their own v4 Desktop system.. It was built from scratch using the latest version of PicoChess (v4.2.2) and the current RPiOS Trixie Desktop release, with all OS updates.

The Lite image for the DGTPi is under development and will use DietPi as the underlying OS, which 'should' allow it to run better on the stock DGTPi. It should be available soon.

Here is the link to the Desktop image:

PicoChess v4 Desktop Image (4.1 GB)

Be sure to read the enclosed Readme.txt document for important info.

Randy

[Johan Sjöblom]

Thanks Randy. This will make it easier for many to test the version 4.

[Johan Sjöblom]

PS. Next time you update master you can change the piece set (pieces=) on the web client. And you can still change the colour (web-board-theme=)

Courtesy DJ Dekker

[Randy Reade]

Hold off before downloading this image. For some reason it is missing the /opt/picochess/install-picochess.sh file. Kind of important. You can download it from Johan's github or attached here.

Randy

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[RandyR]

Compressing now. The good news is that it will include DJ's new feature of being able to change pieces on the web board. I'll reply here when it is upoaded.

Randy

[RandyR]

Fixed mage is uploaded.

Randy

[oeste...@gmail.com]

Hello Randy

Thanks a lot for your efforts! I gave up building an image from GitHub, since the image would not boot into the desktop/picochess GUI, but only to the command line (I had to force it by manually typing the "startx" command).

Unfortunately I now get the same error from your image. My Pi4 still only boots to the command line. I can still force it into graphical mode by typing "startx", so basically nothing has changed for me.

Could the problems be caused by the fact that my Pi4 is connected to a 7" Elecrow 1024*600 touch screen display? This display worked fine with Picochess 3.1 (my Pi automatically booted into the desktop/picochess GUI). I copied the config.txt file from my Picochess 3.1 image to your 4.2.2 installation to avoid getting the error "No display", and the screen seems to work with your image, but as previously stated it still only boots to the command line.

Any ideas?

Regards

Torben 

[Randy Reade]

Yes, it's possible the display isn't supported. Is it possible to test with a different monitor? Also, startx isn't really useful unless you switch to X11 since the image is set for Wayland. I suppose it could be a Wayland issue, too. Maybe check online for similar reports. That would also explain why it worked in the past as the older images were set up for X11.

I'm sure there's a solution out there.

Randy

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[RandyR]

Just a note concerning the Desktop image - if you are not connected to a network (i.e. Ethernet cable) when you first boot the Pi, it can happen that the kiosk browser fails to show the webserver. To fix this you can connect a keyboard and press F5 to refresh Chromium, or connect an Ethernet cable to your network, login via SSH and type 'sudo reboot'. The next boot should show the webserver interface in the kiosk (even if you disconnected the Ethernet cable). You will only notice this if you have a monitor attached.

Randy

On Friday, February 27, 2026 at 12:59:35 PM UTC-6 RandyR wrote:

[oeste...@gmail.com]

Hi Randy

Well, you were right (of course) :-) 

My Elecrow 7" 1024*600 touch screen display was the problem ... but there was a solution out there.

I decided to try and build a Picochess 4.2.2 image myself by following the guide on Johan Sjobloms Github page. I used Raspberry Pi Imager to flash the latest Trixie-based Raspberry Pi OS 64-bit to a 64GB MicroSD-card. At first nothing seemed to work, as the boot process quickly spilled over into a display error message: "No Signal". 

 

I used Grok to guide me through every time I ran into an issue. It was really helpfull and identified my display in connection with KMS as the issue. I therefore started by muting all KMS in config.txt. This removed the "No Signal" error, and my Pi booted to the prompt. Still, I was only able to get into desktop mode by typing "startx" at the prompt. Grok correctly nailed down that my screen was not able to run full KMS. The solution was surprisingly simple: Just switch to fake KMS. This means I only needed to edit one single letter in the KMS command in config.txt by changing from "dtoverlay=vc4-kms-v3d" to "dtoverlay=vc4-fkms-v3d".

Also I added a few lines at the botton of config.txt to ensure correct display output:

hdmi_force_hotplug=1

hdmi_group=2

hdmi_mode=87

hdmi_cvt=1024 600 60 6 0 0 0

Now my Pi4 finally booted automatically into desktop mode ... but picochess GUI did not start (though picochess was running in the background and accessible via the web server). Grok then helped me to activate kiosk mode. BAM! Now my Pi automatically booted into first desktop mode and then into picochess GUI!

Still, I had no sound.

Grok also helped me here. I just had to add a few more lines in config.txt:

# Force HDMI audio even if EDID doesn't report it
hdmi_force_edid_audio=1

# Ensure HDMI is treated as having audio (common fix for custom modes)
hdmi_drive=2   # This enables HDMI with sound (DVI mode=1 disables audio)

Reboot and ... everything finally works!

Hopefully this information will be helpfull to other picochess fans with custom HDMI displays.

Regards

Torben

[Randy Reade]

Glad you solved it, Torben. 😊

To view this discussion visit https://groups.google.com/d/msgid/picochess/eb46503c-f582-4f73-a92f-5433f8001eb4n%40googlegroups.com.

[Henri]

Hi Randy,

I've installed your v4 Trixie desktop image and it works splendidly on my P5. However, I encounter a strange problem when using my P4 with 7 inch touchscreen. After burning the image I added the following lines to /boot/firmware/config,txt

hdmi_force_edid_audio=1
max_usb_current=1
hdmi_force_hotplug=1
config_hdmi_boost=7
hdmi_group=2
hdmi_mode=87
hdmi_drive=2
display_rotate=0
hdmi_cvt 1024 600 60 6 0 0 0

And I changed 'dtoverlay=vc4-kms-v3d' to 'dtoverlay=vc4-fkms-v3d'

This is standard procedure for all picochess images on this 7 inch touchscreen and until now it worked flawlessly to get a proper desktop. That is the case now too, but the touchscreen is not working at all. Strangely, when I use VNC on another machine  I can control the buttons with a mouse and after that the touchscreen starts working...

When I stop picochess and go back to the desktop I can see the icon of a virtual keyboard in the taskbar which opens when I start the browser or the terminal.

What is going on and how do I solve this? Thanks in advance for some insight!

Henri

Op vrijdag 27 februari 2026 om 19:59:35 UTC+1 schreef RandyR:

[Randy Reade]

Hi Henri, 

Yes. That's an interesting problem. I will have a look tomorrow when I have some time. I have a touchscreen I can test. I know there are many different screens out there so not sure I'll be able to help. You could try using X11 and see if there is any change. Or hook up a USB mouse and see if that also activates touch. Could the touch function be 90° out of sync with the displayed image? 

What monitor is it?

Randy

[Randy Reade]

Hi Henri,

I tested a new install of the Trixie Desktop image on my Pi4b inside a 7-inch Touchscreen case (Eviciv) and it works right away without changing to the fkms driver. It's an HDMI display, not DSI.

Randy

[Henri]

Hi Randy,

When I change 'vc4-fkms-v3d' back to 'vc4-kms-v3d' I get no screen at all, only 'no signal'

# Enable DRM VC4 V3D driver
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

Henri

Op dinsdag 3 maart 2026 om 17:11:53 UTC+1 schreef RandyR:

[Henri]

Randy,

By the way, everything works fine when using X11, including the touchscreen.

Henri

Op dinsdag 3 maart 2026 om 17:11:53 UTC+1 schreef RandyR:

Hi Henri,

[Randy Reade]

Not sure what it could be. Maybe try moving the USB cable to a different port. I don't think 'max_usb_current=1' does anything any more (since Bookworm?). Can you switch back to kms and Wayland, reboot and log in via SSH? Then run 'sudo raspinfo && sudo chown pi:pi raspinfo.txt' and paste the raspinfo.txt in your reply or send it via Reply to author.

Randy