[Feature Request] Support for UF2 files

Hi!

I think that it might be useful for ev3duder to have the ability to handle UF2 files. The format is seems like just a block-based file container. It is documented here and here is a reference implementation that looks like some older version of it is running on the actual brick.

In particular, I have the following functionality in mind:

Packing UF2 files. This would allow one to upload C4EV3 programs by dropping them to the emulated file system.
- The UF2 files produced by MakeCode have files internally named like Projects/AAA.elf and Projects/AAA.rbf. The brick then extracts them to /home/root/lms2012/prjs/BrkProg_SAVE. I don't know yet if it is possible to upload files to a different location.
- Depending on whether it is possible to use nonstandard destinations, it may be good to include some path-mapping functionality to increase flexibility. One of the solutions could be to behave like tar does - interpret the file paths relative to CWD and put them like that to the UF2.
Unpacking UF2 files. This would allow one to inspect the contents of the files. This would just unpack the file and directory structure contained in the UF2. I don't think path-mapping would be useful here.
Uploading UF2 files via the LEGO USB protocol. This would combine the unpacking functionality with the upload functionality currently present in ev3duder. This would be helpful on Linux, where there are problems with mounting the emulated file system. The path mapping in this case may be easier: Projects/... would go to the BrkProg_SAVE directory and other paths would be interpreted directly.

Best regards,

Jakub

It turns out path mapping does not need to be configurable. The uf2d executable in the stock firmware contains some strings looking exactly like https://github.com/microsoft/uf2-linux/blob/751b0f4e589583012ab6e3fac4a86f239933257b/uf2daemon/fat.c#L246.

"Projects"       -> "/mnt/ramdisk/prjs/BrkProg_SAVE"
"SD Card"        -> "/media/card/myapps"
"USB Stick"      -> "/media/usb/myapps"
"Temporary Logs" -> "/tmp/logs"
"Permanent Logs" -> "/mnt/ramdisk/logs"

However, compared to how uf2d handles this currently, I'd always create a separate directory for a given program. This would help with program deletion not only Linux, but all platforms, as it seems that it is not possible to bypass the directory mapping.

Therefore I propose the following command line interface:

ev3 uf2 pack <output uf2 file> <brick directory> <files...>
ev3 uf2 unpack <output directory> [--no-paths] <uf2 files...>
ev3 uf2 upload [--uf2d] <uf2 files...>
ev3 uf2 remove [--uf2d] <uf2 files...>

c4ev3 / ev3duder

[Feature Request] Support for UF2 files #15