Extract py or mpy from Spike Prime

[QuirkyCort]

Are there any ways to extract either the py or mpy file from a Spike Prime? I have a team lose their code, but they still have a copy on the Spike Prime.

I can get into the REPL, but import os don't work, so I can't list the files. Tried guessing the file names with open('XXX', 'r'), but no success there either.

[laurensvalk]

Hi @QuirkyCort - nice to see you here. Great work on your simulator!

The .py files are not stored on the hub. As you probably know, the .mpy is a compiled format so may still need further deciphering to be useful.

There isn't currently a way to extract the .mpy file easily, but since you are quite experienced I can make a small modification to the firmware for you so you can not just read the user data but also your own program.

You'll be able to read the bytes, from which you could piece together the .mpy file(s).

Does that sound useful enough?

[QuirkyCort]

Thanks. That would help. Just to be sure, writing a new firmware won't erase the user program?

Also, just for my own understanding, doesn't Pybricks use a filesystem? I've worked with micropython on the ESP32 and Pi Pico, and have expected Pybricks to have a filesystem on the internal flash.

[QuirkyCort]

Unfortunately, I do not know the installed Pybricks version, only that the micropython is 1.20. The Spike does not belong to me, and I will only have access to it next Tuesday.

[laurensvalk]

That's recent enough :)

[laurensvalk]

Do you have a SPIKE Prime Hub to try it out yourself with a simple program first?

• I just tried uploading this program. (On the students hub, of course skip this step)

• Make sure you are on the latest firmware.
• Read the existing bytecode chunk by chunk on the REPL. The instructions are in the first post of: pbio/sys/program_load: Allow reading user program. pybricks-micropython#243

For my test I got:

>>> hub.system.storage(PROGRAM_START + 4, read=61)
b'0\x00\x00\x00__main__\x00M\x06\x00\x1f\x03\x01\x10hello.py\x00\x0f\x81w\x05\rHello, world!\x00`\x08\x02\x01\x11\x02#\x004\x01YQc'

The part starting with M\x06 is the .mpy file.

[QuirkyCort]

Thanks. I don't have a Spike with me now, but I'll try to get one over the weekend and test it out.

[laurensvalk]

This functionality is now included in the stable firmware, so you don't need to install anything custom anymore to follow these steps.