I wouldn't put the F.
I would trust that it's so obvious to people that there is no firmware in this product and hence why the F would be missing from the letters.
As much as I would hope that people would be thinking that carefully and rigorously when looking at the symbol, I think you and I both know that the majority of people are going to interpret the symbol at a glance and mostly just look at its "density" -- I'm pretty sure only a small minority of people would connect all those dots.
I can appreciate the desire to have a "fully decked out" gear symbol with all the letters when you are giving away everything in he design, and I realised this at the time but didn't really have a good solution for that scenario.
Is clarifying the definition of F as I've suggested not a good solution? It's not even changing the definition, just clarifying what is currently a grey area. To make it crystal clear, I'm suggesting that the presence of F means "there is no closed-source firmware" (read: "no annoying roadblocks here!"). This definition is logically
totally identical to "all firmware is open source"*, but the former makes it perfectly clear that F is perfectly allowable for an analog board -- and thereby preventing analog boards from being pretty arbitrarily disallowed from having fully decked out gear symbols. I know that you'd prefer that people not blindly demand fully decked-out symbols, but you sort of know that a lot of people are going to do so regardless, and to leave purely analog boards with the resulting marketing disadvantage as a result seems unfortunate.
* !AnyOf([a, b, c, ...]) === AllOf([!a, !b, !c, ...])
I also wouldn't put the F in there. It implies there IS something.
This is a worrying implication -- it implies that the F only means "open source firmware is present". What if there are two programmable chips, one open source, the other (actually doing all the work) closed source? If we don't insist that the definition is "
all applicable firmware is open source", then
If anything, I would put a big dot in the corresponding cog - but anything used to signify there is no specific component should really be spelled out in the definition.
This is a fine compromise, I would probably adopt this idea.