Pardon my ignorance of N810 hardware, but I think the blue keys you reference are the Fn-shifted keys, for e.g. numerals? If so, that's not an issue of closed-source, you just need to use xmodmap to make an appropriate mapping. There's one here that FatalSaint made for Debian. More troublesome, though, is the fact that the exact product eyco linked to was for x86, not ARM; it cannot work. I don't know if there's an ARM version available, but that will be necessary for any possibility of running on the N810.