How do I dual boot with custom main.py?

[fatherchaos]

Hi,
I'm trying to flash a dual boot firmware to the PrimeHub with a modified main.py. My goal is to load a custom main.py to use when the unit boots to pybricks and charge the unit in the regular firmware. This is intended for first lego league.

I can use the website install.pybricks.com to install the dual boot firmware, but there is no option to select my custom firmware.

When I use "py pipx run pybricksdev -flash primehub.zip" the primehub must be in dfu and does not install the dual boot firmware. I found that oybricksdev had a -dual-boot argument in January, but the command does not appear to work now.

Can someone guide me through how to install a modified dual boot firmware with custom main.py?

[laurensvalk]

Can someone guide me through how to install a modified dual boot firmware with custom main.py?

This is not currently supported. Since the Prime Hub has 30Mb of storage space, our plan is to enable that instead of having to flash something every time.

Though I can see that this is not too helpful in the short term.

In case you have more than one set, is it an option to use the second Prime Hub to charge the battery in, and then swap them?

[fatherchaos]

Hi, I just want to make sure I'm on track with this.

I'm hoping to have a short term solution available for the kids to help them test the primehub using pybricks. What would be the simplest option to have the firmware find a main.py or main.mpy? If I can compile/upload one python file that might be the fastest for the students. Right now I envision the easiest path would be to use the os upload function and just overwrite the existing main.py or main.mpy file stored in _pybricks/.

I'd like to help with the rudimentary file storage for the firmware, but do not know where to start.

In the meantime I have made a local copy of install.pybricks.com to make a hacked together solution to compile the firmware with pybricksdev -compile and use that file (with updated hash) on my local copy of install.

[laurensvalk]

I don't think we'll be able to do this in the short term, I'm afraid.

Is it an option to just use dual boot with Pybricks Code most of the time, and only use pybricksdev to occasionally test the single-boot-with-script approach, just to make sure things are working for competition day?

Right now I envision the easiest path would be to use the os upload function and just overwrite the existing main.py or main.mpy file stored in _pybricks/.

There's only the installation script in that folder, there is no main script.

[fatherchaos]

Right now we are using the dual boot from pybricks code (beta). This works well enough for now for the little bits they are making. We plan to use pybricksdev to flash with the full program as you mentioned.

My thought was to upload the main.py using the same method that the install script from install.pybricks does, snippet below for reference:

case 1:
                    _a.sent();
                    return [4 /*yield*/, uploadFile('install_pybricks.py')];

For this case I'd make a simple button to perform the following:

case 1:
                    _a.sent();
                    return [4 /*yield*/, uploadFile('main.py')];

which would create the file _pybricks/main.py

If the firmware can see that file then I can stick with a single upload for main.py or a compiled main.mpy

[laurensvalk]

If the firmware can see that file then I can stick with a single upload for main.py or a compiled main.mpy

To reiterate, there is currently nothing in the firmware that can read files from file storage.

But there's some good news as well. We've been making some initial progress on saving the program as it gets downloaded to the hub.

If all goes well, that means students can just use Pybricks Code and dual boot without further modifications.

[fatherchaos]

That sounds great. Is there any way I can help?