Custom firmwares using Docker containers.

[Hristo-Nikodimov-Nenkov]

Greetings.

I've created a set of Docker containers available here
All containers and scripts are available here

You can open issue or discussion if you run on any problem or have suggestion.

[Josverl]

Thanks for sharing,

But I wonder if you are aware of mpbuild and it's container definitions ?

Is there anything specific that you added that you would call out ?

[Hristo-Nikodimov-Nenkov]

I have not used mpbuild.
I've created this containers to streamline the build of custom firmwares and allow to work on code at the same time.
All code in /modules is frozen, /lib is uploaded as files.
You can freeze both main.py and/or boot.py by setting env variable
See the full documentation here

I've created them because the GitHub Actions on ESP32 based boards throws - "No space left"
I wanted to use it with Woodpecker CI on my home lab and needed build-ready containers for both micropython and micropython with esp-idf (ESP32 boards).

[Josverl]

You can freeze both main.py and/or boot.py by setting env variable

Assuming you mean to cross-compile to .mpy, That will break the build, as the wont be executed if the are not .py files

[Hristo-Nikodimov-Nenkov]

If you do not upload the .py the frozen one is executed.

If no /modules directory exists and both FREEZE_MAIN and FREEZE_BOOT are "false", the container builds plane firmware.
However:

• when /modules has any .py files then the 'freeze("modules", opt=3)' is added to manifest
• when FREEZE_MAIN is "true" the 'freeze(".", script="main.py", opt=3)' is added
• when FREEZE_BOOT is "true the 'freeze(".", script="boot.py", opt=3)' is added

This allows for "flash and forget" firmware builds and at the same time you can work on code in /lib, you just have to add main.py and/or boot.py to "micropico.pyIgnore" to prevent the upload of the .py file.

All is done by baked-in build_firmware.sh, but I also added the ability to overide both build_firmware.sh and manifest.py for more flexability.

[Hristo-Nikodimov-Nenkov]

How to make my custom firmware show like:
MicroPython v1.27.0 on 2025-12-09; WeAct Studio RP2040 with RP2040
in the REPL
It aways shows: -dirty?

Is there a variable I should set, or I have to change files?

[mattytrentini]

As @Josverl alluded to, I maintain mpbuild and similar build containers (arm, rp2350-riscv) to those you've published that are used by mpbuild. The published version of those containers are also available in the official MicroPython docker hub.

Please take a look and see if you can reuse them - or suggest improvements; it'd be better to have one place for folks to go looking for these resources!

BTW you shouldn't need to create a container for esp32 as Espressif publish excellent esp-idf containers that can be used directly.

[Hristo-Nikodimov-Nenkov]

I've looked over the documentation and they do not automate anything. Just a base container.
If I use them I still need to have all files prepared like manifest.py
In my variant this is handled by the baked-in build_firmware.sh
It generates the manifest.py ( when needed). And copies modules, main.py, boot.py and manifest.py to the board directory.
The generated firmware is copied in $PROJECT_DIR/dist when build is finished.

It is ment to be as hands-off as possible.

[mattytrentini]

There should be no reason to put anything except tooling inside the container; certainly no specific MicroPython files. Just the build environment. Then you use the container as an environment. Doing it this way means it's much easier to keep the container updated - and leaner. Take a look at how mpbuild uses the build containers.

If you want to bake-in more then go ahead, but I think you'll find it counter-productive!