PicoChess v4 Image [8 June 2025]

[RandyR]

Hi Everyone.

I decided to make a smaller image to speed up the download for people. All I did was remove the pico_backups folder which saved around 6GB. If you already have the image from 7 June 2025 you do not need to download this one, but I also made a change to the browser startup script (kiosk.sh). It will now wait for PicoChess to start before launching the browser (before it just waited a specific number of seconds). I'll attach it here for those who want to replace it themselves (it's located in the pi home folder).

If you do use this image, note that the next time you update it will take about 9 minutes (on a Pi4) as the backup I removed for this image gets re-made. Once the update is finished, the web server will start. Just be patient.

And a reminder - if you see any functionality issues while testing and would like to let Johan know, either open a topic on this forum or, if you have a (free) GitHub account, you can open an Issue on Johan's repo (if not already opened).

Randy

Here is the link to the image:

PicoChess v4 Desktop (6.8 GB)

[RandyR]

Just a note to anyone who replaces the engines folder on the v4 image with the one from my v3.4 image (to get updated engines to play with), if you want to run Linux engines you'll have to install Box64 via Pi-Apps. Windows engines are using Hangover rather than Wine64 so Box64 wasn't needed or installed. The only Linux x64 engine included in v3.4 was StockfishDD.

Randy

[Johan Sjöblom]

When you are updating Pico V4 beta from the menu your engine folders might be overwritten as it contains engines in the repository. We have opened an issue #88 https://github.com/JohanSjoblom/picochess/issues/88

I have now made a first fix to the picochess-install.sh script so that it protects the engine files from being overwritten. HOWEVER NOTE: your machines still contain the old picochess-install.sh so if you run an update you can potentially lose engine setups. Now there are two ways to avoid this:

1) Run the protection command manually to protect your engines, NOTE: do not use sudo here.

open a terminal and do

> cd /opt/picochess

> find engines -type f -print0 | xargs -0 git update-index --skip-worktree

This will mark all your engines to be "left alone" when git pull is updating your system

2) Download the new install-picochess.sh script manually before asking for an update so that the new protection line is there when it updates. This is a straight copy from the Readme file:

> open a terminal and do

> cd /opt/picochess

> wget -L https://raw.github.com/JohanSjoblom/Picochess/master/install-picochess.sh

> chmod a+x install-picochess.sh

If you perform either of these your engine folder should be safe. I do recommend the first one. For me it complained about McBrain on my Pi4, but it should be fine anyway.

If you have not changed anything in the V4 engine folder you dont have to do anything, you can just update, and you will still get the latest LC0 and Stockfish versions, 0.32 and 17.1 I believe. After the next update you can go ahead and do whatever you want with the engine folder.

BR, Johan

PS

Next steps / future

The next step that we will do as part of the issue #88 is to move the repository engines to a folder called engine-examples. On new installs they would be copied as a one-time action to your engine folder, or if you have deleted your engine folder it would be copied. But this has not been done yet... Its still under work. When we do this anyone who has not protected their engines either by updating or by using one of the above will lose the engines on an update. So I will wait a while to do this.

As I will continue to experiment with LC0 playing the very human networks like meangirl, and badgyal and maia etc I will probably add those networks to the repository so that you can all test them when I have my own test setup ready.

DS

[RandyR]

>>If you perform either of these your engine folder should be safe. I do recommend the first one. 

>>For me it complained about McBrain on my Pi4, but it should be fine anyway.

If you try to mark any files that aren't in the git repo, it will complain. I'm not sure why it only lists certain files and not all. So it's really just preventing any files in the folder (engine folder in this case) from being added to your local folder (or overwriting files in your local folder). If you run 

git ls-files -v . | grep ^S

in the /opt/picochess folder it will show the repo files that were marked.

Randy

[Johan Sjöblom]

This is for brave testers of V4. Unfortunately there is a breaking change that will give you problems on the next update. This is a one-time breaking change to make sure that after this your engine folders stay exactly as you made them. Here is some instructions that you could use but there might be users here who know how to do this better.

On a command terminal

# start in the pico directory

cd /opt/picochess

# 1. Move your local engines folder to a safe place
mv engines /home/pi/engines_backup

# 2. Make sure you are on the master branch
git checkout master

# 3. Reset your local repository to the latest version
git fetch origin
git reset --hard origin/master

# 4. Move your engines back
mv /home/pi/engines_backup engines

# 5. Run the install script again
./install-picochess.sh

I am working on a Trixie update so another option is to avoid updates until we have a new Trixie image

I will also fix it so that you dont get the lco_weights file every time, but thats on the todo list still…

BR, Johan