Update for aarch64 assets, mainly Rodent III/IV related

[DJ Dekker]

Hi all,

I have prepared an unofficial community test package for PicoChess issue #468.

The updated assets:

• fix several Rodent III personalities and opening books;
• make Rodent IV correctly activate personalities such as Tal and Karpov;
• correctly return Rodent IV to its normal style and books when selecting a regular Elo level;
• includes the latest Fairy-Stockfish configuration, with four Antichess playing levels.

The package has been tested successfully on a Raspberry Pi 5, but more testers are very welcome.

Download the files here:

Google Drive – PicoChess test package

Please note:

• These are unofficial test files for 64-bit Raspberry Pi systems only.
• All three .tar.gz files are needed.
• Please read README-issue468.txt before installing.
• Back up your existing engine files first.
• The package does not contain versions for armv7l (older Raspberry Pi) or for x86_64 (Windows, Intel Mac).

If you test the package and encounter any difficulties, please report your Raspberry Pi model.

The engine package does not contain the new Stockfish 19 yet. I'm currently investigating which engines are out of date, and am in the process of building and testing up-to-date versions.

Greetings,

DJ

[DJ Dekker]

I have now tested these five updated engines on RPi5 and added them to the aarch64 assets file:

StockfishNN 19

ArasanNN 26.0 (along with updated .uci and .nnue files)

Patricia 5.1 (along with updated .uci file)

ShashChess 41.2

Vajolet2 3.2.0

Op zondag 4 oktober 2026 om 12:55:49 UTC+2 schreef DJ Dekker:

[Andrea Gatti]

Hello DJ Dekker,

thank-you for these additions, I'd like to go ahead and use them on my Rpi4.

I'll download it and try to test it on my system.

If I may, I'd like to ask you a clarification about Stockfish.

It is related to its name in picochess: why are we naming it "StockfishNN 19"?

If it refers to the fact that it uses an embedded (or external) neural net, it is to be said that Stockfish won't work without a net. In other words, every "Stockfish" since I believe SF13, is a "StockfishNN". Moreover, "StockfishNN" simply doesn't exist..

I'm looking forward to your reply -- I may have overlooked something here.

Thanks!

AG 

[DJ Dekker]

Hi Andrea,

PicoChess ships with Stockfish 16.0, the last version that used HCE (Hand Crafted Evaluation). From Stockfish 16.1 on, the engine removed HCE and has been using a neural network (NNUE). I believe we kept Stockfish 16.0 as the analysis engine because it is smaller and puts less stress on 32-bit Raspberry Pis.

Stockfish 19 is called StockfishNN 19 just like all other NNUE engines in the /opt/picochess/aarch/NNUE folder. You're right that StockfishNN doesn't exist as such, just like ArasanNN or RubiChessNN.

Greetings,

DJ

Op maandag 5 oktober 2026 om 22:01:26 UTC+2 schreef andreag...@gmail.com:

[Andrea Gatti]

Hi DJ, many thanks, this actually explains.

On my local copy, I have renamed StockfishNN 19 to Stockfish, just to keep it aligned with what the engine real name is. My understanding is that Johan's update (git or whatever is used) does not overwrite the engines' files nor the names in engines.ini and the other files, so I should be safe.

You also incidentally covered another question I had -- why we kept an old engine as a (local) Tutor engine. Again, I have chosen a remote engine running on my windows box as a remote Tutor, but with SF19 / 1 thread, on the Rpi, as a fallback. Using htop, a local SF19 shows no stress signs during a game/analysis session.

Thanks!

AG

[Andrea Gatti]

Sorry for the typo: I renamed it to "Stockfish 19" not just "Stockfish" -- sorry.

AG

[Johan Sjöblom]

Yes correct, the Picochess Update does not touch any engines folders if they already exist. That is by design as users wants to manage the engines themselves.

If DJ Dekker now has updated the resource files its great, new installations will get them, and for old untouched engine installations you could use the install-engines script with "lite" parameter..

I chose a bad parameter name "lite" for the install-picochess to pick the larger package as at that time back then I thought we would make a "large". However there has been some confusion on that "lite" has some relationship to the SD image type lite, which is not the case. So I am thinking that we should rename the parameter from "lite" to "large". So we have "small" or "large" when you install the first time. For a quick first install without parameters it would default to "small" as it does now, because "large" takes a lot of download time.

And yes, the "last non NNUE" Stockfish is there as a fallback engine both in the resource file and on the latest SD images (at least in my understanding).

// Johan

[Andrea Gatti]

Hello Johan, this reminds me to ask you a clarification about what you just wrote:

- What is the command line I can use to initiate an update to picochess, manually?

- What command shall I use to therefore just update the engines (without impacting my own ones)?

Thanks!

Andrea

[Johan Sjöblom]

Hello Andrea,

To update Picochess manually, run:

cd /opt/picochess
sudo ./install-picochess.sh pico

The pico parameter skips the operating-system update and updates Picochess itself. When you do not specify small or lite, existing engine folders are left untouched.

We currently do not have a supported command that updates engines in place without affecting your own engine setup. The existing engine reinstall path backs up the current engine folder and installs a new package. It is mainly a destructive replacement/start-over mechanism, not a version-aware update or merge.

To support proper engine updates, we would first need a stable and agreed folder structure across SD images and user installations. Picochess would then need logic to download engine metadata, compare installed versions and update only the relevant files. We do not have that architecture today.

The engine and MAME installation packages are mainly intended to get a clean stock SD image started. At the moment, if someone wants the latest complete engine build, the most reliable source is probably Randy's latest SD image. Copying engines from there is still a manual operation, and the existing engine folders should be backed up first.

// Johan

On Tue, 06 Oct 2026 11:55:11 -0700, Andrea Gatti <andreag...@gmail.com> wrote:

Hello Johan, this reminds me to ask you a clarification about what you just wrote: - What is the command line I can use to initiate an update to picochess, manually? - What command shall I use to therefore just update the engines (without impacting my own ones)? Thanks! Andrea Il giorno martedì 6 ottobre 2026 alle 10:31:26 UTC+2 messi...@gmail.com ha scritto: > Yes correct, the Picochess Update does not touch any engines folders if > they already exist. That is by design as users wants to manage the engines > themselves. > If DJ Dekker now has updated the resource files its great, new > installations will get them, and for old untouched engine installations you > could use the install-engines script with "lite" parameter.. > I chose a bad parameter name "lite" for the install-picochess to pick the > larger package as at that time back then I thought we would make a "large". > However there has been some confusion on that "lite" has some relationship > to the SD image type lite, which is not the case. So I am thinking that we > should rename the parameter from "lite" to "large". So we have "small" or > "large" when you install the first time. For a quick first install without > parameters it would default to "small" as it does now, because "large" > takes a lot of download time. > > And yes, the "last non NNUE" Stockfish is there as a fallback engine both > in the resource file and on the latest SD images (at least in my > understanding). > > // Johan > > On Tuesday, 6 October 2026 at 00:25:40 UTC+3 andreag...@gmail.com wrote: > >> Sorry for the typo: I renamed it to "Stockfish 19" not just "Stockfish" >> -- sorry. >> >> AG >> >> Il giorno lunedì 5 ottobre 2026 alle 23:23:38 UTC+2 Andrea Gatti ha >> scritto: >> >>> Hi DJ, many thanks, this actually explains. >>> >>> On my local copy, I have renamed StockfishNN 19 to Stockfish, just to >>> keep it aligned with what the engine real name is. My understanding is that >>> Johan's update (git or whatever is used) does not overwrite the engines' >>> files nor the names in engines.ini and the other files, so I should be safe. >>> >>> You also incidentally covered another question I had -- why we kept an >>> old engine as a (local) Tutor engine. Again, I have chosen a remote engine >>> running on my windows box as a remote Tutor, but with SF19 / 1 thread, on >>> the Rpi, as a fallback. Using htop, a local SF19 shows no stress signs >>> during a game/analysis session. >>> >>> Thanks! >>> >>> AG >>> >>> >>> >>> Il giorno lunedì 5 ottobre 2026 alle 22:15:30 UTC+2 DJ Dekker ha scritto: >>> >>>> Hi Andrea, >>>> >>>> PicoChess ships with Stockfish 16.0, the last version that used HCE >>>> (Hand Crafted Evaluation). From Stockfish 16.1 on, the engine removed HCE >>>> and has been using a neural network (NNUE). I believe we kept Stockfish >>>> 16.0 as the analysis engine because it is smaller and puts less stress on >>>> 32-bit Raspberry Pis. >>>> >>>> Stockfish 19 is called StockfishNN 19 just like all other NNUE engines >>>> in the /opt/picochess/aarch/NNUE folder. You're right that StockfishNN >>>> doesn't exist as such, just like ArasanNN or RubiChessNN. >>>> >>>> Greetings, >>>> DJ >>>> >>>> Op maandag 5 oktober 2026 om 22:01:26 UTC+2 schreef >>>> andreag...@gmail.com: >>>> >>>>> Hello DJ Dekker, >>>>> >>>>> thank-you for these additions, I'd like to go ahead and use them on my >>>>> Rpi4. >>>>> >>>>> I'll download it and try to test it on my system. >>>>> >>>>> If I may, I'd like to ask you a clarification about Stockfish. >>>>> >>>>> It is related to its name in picochess: why are we naming it >>>>> "StockfishNN 19"? >>>>> If it refers to the fact that it uses an embedded (or external) neural >>>>> net, it is to be said that Stockfish won't work without a net. In other >>>>> words, every "Stockfish" since I believe SF13, is a "StockfishNN". >>>>> Moreover, "StockfishNN" simply doesn't exist.. >>>>> >>>>> I'm looking forward to your reply -- I may have overlooked something >>>>> here. >>>>> >>>>> Thanks! >>>>> >>>>> AG >>>>> >>>>> >>>>> Il giorno lunedì 5 ottobre 2026 alle 21:51:17 UTC+2 DJ Dekker ha >>>>> scritto: >>>>> >>>>>> I have now tested these five updated engines on RPi5 and added them >>>>>> to the aarch64 assets file: >>>>>> >>>>>> StockfishNN 19 >>>>>> ArasanNN 26.0 (along with updated .uci and .nnue files) >>>>>> Patricia 5.1 (along with updated .uci file) >>>>>> ShashChess 41.2 >>>>>> Vajolet2 3.2.0 >>>>>> >>>>>> >>>>>> Op zondag 4 oktober 2026 om 12:55:49 UTC+2 schreef DJ Dekker: >>>>>> >>>>>>> Hi all, >>>>>>> >>>>>>> I have prepared an unofficial community test package for PicoChess >>>>>>> issue #468 <https://github.com/JohanSjoblom/picochess/issues/468>. >>>>>>> >>>>>>> The updated assets: >>>>>>> >>>>>>> - fix several Rodent III personalities and opening books; >>>>>>> - make Rodent IV correctly activate personalities such as Tal >>>>>>> and Karpov; >>>>>>> - correctly return Rodent IV to its normal style and books when >>>>>>> selecting a regular Elo level; >>>>>>> - includes the latest Fairy-Stockfish configuration, with four >>>>>>> Antichess playing levels. >>>>>>> >>>>>>> The package has been tested successfully on a Raspberry Pi 5, but >>>>>>> more testers are very welcome. >>>>>>> >>>>>>> Download the files here: >>>>>>> >>>>>>> Google Drive – PicoChess test package >>>>>>> <https://drive.google.com/drive/folders/17t_rzkG85BOZogdqPPQSfmUH75oDUSOI?usp=sharing> >>>>>>> >>>>>>> Please note: >>>>>>> >>>>>>> - These are unofficial test files for 64-bit Raspberry Pi >>>>>>> systems only. >>>>>>> - All three .tar.gz files are needed. >>>>>>> - Please read README-issue468.txt before installing. >>>>>>> - Back up your existing engine files first. >>>>>>> - The package does not contain versions for armv7l (older >>>>>>> Raspberry Pi) or for x86_64 (Windows, Intel Mac). >>>>>>> >>>>>>> If you test the package and encounter any difficulties, please >>>>>>> report your Raspberry Pi model. >>>>>>> >>>>>>> The engine package does not contain the new Stockfish 19 yet. I'm >>>>>>> currently investigating which engines are out of date, and am in the >>>>>>> process of building and testing up-to-date versions. >>>>>>> >>>>>>> Greetings, >>>>>>> >>>>>>> DJ >>>>>>> >>>>>> -- You received this message because you are subscribed to the Google Groups "PicoChess" group. To unsubscribe from this group and stop receiving emails from it, send an email to picochess+...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/picochess/424e1452-aa4e-444a-a8bc-7ec16ffa3fden%40googlegroups.com.