[Battlemesh] What hardware still works?

Jonathan Morton chromatix99 at gmail.com
Tue Mar 1 14:09:16 CET 2016

> On 1 Mar, 2016, at 11:02, Simon Wunderlich <sw at simonwunderlich.de> wrote:
> How exactly are you going to ensure compliance with the FCC rules in terms of 
> software security? If you want to use it in the US, you have to do the same 
> FCC certification, therefore solve the same problem - hopefully in a smarter 
> way.
> I'd be very interested in how your solution looks like, since other vendors 
> can adopt this idea into their firmwares as well to create open routers.

In PCs, the wireless radio is typically on a daughtercard which is certified separately - even when it’s a softmac like ath9k, and the retail product in question is a complete motherboard or even laptop with “integrated wifi”.  Obviously, you can easily change the software drivers on a PC, including putting in a replacement regulatory database (or simply changing the regulatory-domain setting), but somehow that doesn’t invalidate the entire PC’s certification.

I don’t see how a router is fundamentally different from that.  Indeed, I’ve seen plenty of older routers with daughtercard radios - the first Apple Airport Base Station was built around a standard, off-the-shelf PCMCIA card.  I assume any trends towards greater integration are due to cost-per-unit reduction efforts.

So my solution would be to use an off-the-shelf mini-PCI or mini-PCIe wifi daughtercard with its own FCC certification (already done for us!), and plug it into a motherboard which itself has no radio components whatsoever (and thus for which FCC certification as a Part-B device is relatively straightforward).  I assume the case with its antennae will also need approval in combination with the daughtercard, but this should also not be excessively difficult.  Any “closed” firmware required by the daughtercard should be stored on an EEPROM on the card, wired up in such a way that the daughtercard is self-bootstrapping.

Theoretically, *no lockdown* is then required.  You would put in sensible security measures, such as signed software updates, for the sake of security, not bureaucracy. You could even provide an explicit interface for flashing unsigned firmware, with a captcha that simultaneously asserts that a human is present (security), and provides fair warning that using modified firmware to exceed local regulatory emission limits may violate local laws (bureaucracy) and that responsibility for this now falls on the user.

 - Jonathan Morton

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