From my point of view, the main problem is that the "author" seems to have made its emulator from the HxC Floppy Emulator source code (pic firmware + pc floppy encoder) and schematic and doesn't precise it. Of course its project is closed source ...
What i claim is just a small credit/copyright somewhere. After this, he can sell what he want, it's not my business (as written on the GPL...)
It's the second time that this happens, and this becoming tiring...
To me it seems that the main problem is that the "real author" seems uncapable of following up the "or else " bits set by the copyright license he chose to use on his intellectual property, and instead of doing the proper thing about it (like reporting to the owner of the GPL, that is FSF), complains on web forums about how tiring it is - on second insident, already. Imagine how the busybox authors must feel! :hammer:
Maybe you should chose a less "tiring" license in the future?
For what it's worth, I bought HxC USB not many months ago, and would buy SD version too, if available.