@daveallie keep in mind Group5 uses GPL-3.0-or-later (restrictive) while CrossPoint is MIT (permissive), so the resulting binary (if it contains the compiled Group5 lib) could only be distributed under GPL as well. IANAL but you might consider one of these options

1. making everything GPL3
2. keep MIT but add separate build targets with/without Group5 so people can build an MIT-compatible firmware
3. clean-room reimplementation of the format under MIT (feels a bit excessive tho)
4. it seems Group5 changed its license here, can't tell if the previous license is more or less permissive and would allow use of that older version under MIT
5. talk to the Group5 author, maybe they can make this library MIT-compatible

Someone with more experience in software licenses should add more context here but I'm just trying to raise the awareness of this potential issue before it's too late :) Also, thanks for all your work, I couldn't be happier with my new e-reader ❤️

Thanks for your concern @cbix, I did actually talk with @bitbank2 (Group5's author) and confirm that it was ok to include inside of CrossPoint. Perhaps there is a better way to reference this fact through a custom license file.