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Linksys WRT Routers Won't Block Open Source Firmware, Despite FCC Rules (arstechnica.com)
The FCC requires all manufacturers to prevent users from having any direct ability to change RF parameters (frequency limits, output power, country codes, etc). The easiest way for a router manufacturer to comply with FCC's guideline is to block the open source router firmware -- which is what TP-Link has been doing. But thankfully, at least one router manufacturer doesn't think blocking the firmware is the right way to go about it. Ars Technica reports: Linksys has been collaborating with chipmaker Marvell and the makers of OpenWrt to make sure its latest WRT routers can comply with the new rules without blocking open source firmware, company officials told Ars. Linksys' effort stands in contrast with TP-Link, which said it would entirely prevent loading of open source firmware on its routers to satisfy the new Federal Communications Commission requirements. "They're named WRT... it's almost our responsibility to the open source community," Linksys router product manager Vince La Duca told Ars. Cybersecurity experts have urged the router manufacturers to not block open source firmware.
This action is not a violation of the FCC rule in question. That rule defined a chain of responsibility for purposes of assigning blame when and only when someone is using their wireless router beyond the scope of FCC approved frequency/intensity ranges.
For a fine to come about, someone has to flash the firmware (easy it seems) with another firmware that does not respect the FCC mandated boundaries (I think that would require changing the source and recompiling for most of them) and then pick a frequency and power level that is prohibited for WiFi use.
While I forget the order of blame that the FCC decided on, this announcement indicates that Linksys has run the numbers and determined that the increased fanaticism from OSS enthusiasts for their routers will more than offset any anticipated culpability when people misuse their hardware.
Actually, 2.4 GHz and 5 GHz were chosen because they're absorbed more by the atmosphere. 2.4 GHz matches up closely with the resonance of water molecules (which is why microwave ovens operate at 2.45 GHz - they heat up food by pumping energy into the water molecules). And 5.6 GHz is absorbed readily by raindrops for some reason I haven't yet been able to learn (which is why it's handy for weather radar).
Broadcasts on both bands thus attenuate more quickly relative to other frequencies. This not only makes them less useful for long-distance transmissions, but it makes them ideal for unregulated transmissions. The signal blasted by an unregulated device at these frequencies doesn't travel as far through the atmosphere, so the radius of its noise footprint is smaller compared to a different frequency. Basically, you can squeeze more devices closer together without interfering with each other at these frequencies. Both of these "features" make them ideal choices for open frequencies.