The serious answer is to whatever your country’s internet regulation agency is (assuming your in the EU, else you’re out of luck). So for example, in France that would be the CNIL, in Germany it’s the BfDI, etc.
But then again, is it Linux’ fault that publishers refuse to make Linux versions of their games, requiring the users to use hacks to make windows executables work on Linux ?
I mean… Depends what you mean by 100% free firmware… If you mean only the boot firmware, that’s the case for PCs like the ThinkPads T400, T500, R500, W500, X200, as well as the Dell Latitude E6400. Note Libreboot even recommends the latter for new full libre buys, as it can be software-flashed without disassembly.
But if you mean 100% free including EC firmware, wireless firmware, and disk firmware, then this will probably never happen, or at least not until a very very long time.
There are a few ways to investigate, but for that we would need a bit more info. Firstly, what distro do you use ? Try using a different bootloader than GRUB to see if it solves the issue. Otherwise you could also try to use Linux’s UEFI stub.