Item description:

ZIP3DSFX v0.6 by d0k3
ZIP3DSFX is a ZIP-based SFX extractor for the 3DS console. It has two main build modes plus multiple configuration options.

SFX Hard Mode: This mode hardcodes the archive.zip into the ZIP3DSFX.3dsx executable. To use this, rename your ZIP archive to 'archive.zip', put it into the data directory and compile with 'make sfx_hard'.

This will use the smallest amount of memory and will work anywhere.
The archives content can not be changed without compiling anew.
SFX Stub Mode: This mode creates a SFX stub, the actual archive.zip has to be attached to the end of the ZIP3DSFX.3dsx. Compile this with 'make sfx_stub'. Files are attached (on Windows) via 'copy /b ZIP3DSFX.3dsx + archive.zip myZIP3DSFX.3dsx'.

You can simply copy any ZIP archive to the end of the 3DSX to create a new SFX archive.
The resulting .3DSX can (in standard ZIP mode) still be opened in any archiver program on any platform.
This uses more memory and will not properly work with some loading methods.
If you want to customize the SMDH file, edit AppInfo and icon.png in the resources.dir. If you want to further customize ZIP3DSFX overwrite behaviour (among other settings) edit config.h inside the include directory or use predefined config settings def_overwrite_always, def_overwrite_ask, def_overwrite_never, theme_pack or boot_installer. The correct syntax is: 'make [sfx_stub|sfx_hard] CONFIG=[config_name]'. This is untested with large files and archives. Use at your own risk!