If you chose to do it of your own volition, then that's a personal decision (though one I don't recommend because your investors made a calculated wager on you...sometimes wagers lose, and that's the nature of the game they have chosen to play). But if you were asked or pressured into it, they shouldn't have done that, and by doing it voluntarily, you are teaching those investors to expect it of others.
I'm curious if you feel it could have worked out differently if you'd flipped the approach on its head and instead of starting with investment and then the product, you bootstrapped custom radios and built the platform out from there when you had some traction?
I ask partially because I'm in a similar place at the moment with a product (http://mirobot.io) and considering different growth strategies.
Either that or the valuation is inflated artificially 5 fold.
Combine that with other things like preferred shares, and these large investments wind up being horrible for entrepreneurs, unjustly rewarding for the primary investors who are actually risking small sums in exchange for large portions of equity, and unfair for others that invest based upon what the "smart money" invested with a huge headline number.