Licensing review

Not legal advice. This is a summary of the licence position as researched on 2026-10-16.

Component	Licence	How MEGA65 GUI uses it
M65Connect	GPL-3.0	Studied for behaviour only; no code copied or translated
mega65-tools (`m65`, `mega65_ftp`, `etherload`, `romdiff`, …)	GPL-3.0 (newer files GPL-3.0-or-later)	Downloaded at the user's request from the official Filehost and run as separate processes
SharpCompress	MIT	NuGet dependency
CommunityToolkit.Mvvm	MIT	NuGet dependency
System.IO.Ports	MIT	NuGet dependency

Conclusions

Running the tools as separate programs (process execution and parsing their output) is "mere aggregation" under the GPL FAQ. It places no GPL obligations on MEGA65 GUI's own code.
The app does not redistribute the tools. It downloads the official builds from the Filehost at runtime.
- If a future installer bundles them, it must:
  - ship the GPL-3.0 text;
  - keep the copyright notices;
  - give the Corresponding Source for those exact binaries (link to mega65-tools at the commit in the archive name, e.g. 44c63d2);
  - add no installer or EULA terms that restrict users' GPL rights over those tools.
Copying or translating any M65Connect source would make MEGA65 GUI a GPL-3.0 derivative. That includes its Xojo code, key-code tables, D81 code and SD-manager parsing.
- Native features are written clean-room from facts, which are not copyrightable: register addresses, file formats, ROM offsets and CLI flags.
- Planned work this applies to: the remote keyboard, D81 editing and the ROM Configurator.
Do not redistribute:
- FTDI ftd2xx.dll (proprietary);
- closed MEGA65/Commodore ROMs;
- Vivado.
MEGA65 GUI is licensed under the GNU GPL v3 (see LICENSE), the same licence as the official MEGA65 tools and M65Connect.