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So open firmware from the manufacturer is fine, but if you were to modify it and re-flash it yourself you would be breaking the law? I guess that makes sense,

So open firmware from the manufacturer is fine, but if you were to modify it and re-flash it yourself you would be breaking the law? I guess that makes sense, thanks for the clarification!

treesknees 5y ago
I don't think that makes sense at all. One major part of Part 15 from the FCC covers this. A device would fall under the category as an intentional radiator in part 15.1. And in part 15.23, considered a home-built device. § 15.23 Home-built devices. (a) Equipment authorization is not required for devices that are not marketed, are not constructed from a kit, and are built in quantities of five or less for personal use. (b) It is recognized that the individual builder of home-built equipment may not possess the means to perform the measurements for determining compliance with the regulations. In this case, the builder is expected to employ good engineering practices to meet the specified technical standards to the greatest extent practicable. The provisions of § 15.5 apply to this equipment. https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15 https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A... This entire part from the FCC basically states you don't need a license to operate in the frequencies for wifi, bluetooth, etc. You're not breaking a law by recompiling the firmware for your wifi module to fix a bug. You'd be breaking the law if you did so with the intention of operating within licensed spectrum/power levels, for example.
- p_l 5y ago
  The problem starts with the fact that the device doesn't have any way of showing that it was modified, and some of the frequencies involved are license-restricted (especially in 5GHz wifi bands - 2.4GHz is dumping ground free-for-all because of aircraft ovens anyway). So, let's say you modify something with your own firmware, break rules about ISM spectrum - or worse, mess with SDR hard enough you break some licensed spectrum, and upon investigation FCC certification marks are found and the number. Since certification points to vendor, vendor now has to explain why their device went outside of those limits, and might or might not be able to prove that you ran it with unlicensed firmware. So an obviously home build device will go under §15.23 easily, but inconspicuously modified commercially sold device won't - without possibly long court case, that is.
  - franga2000 5y ago
    The FCC is very familiar with inconspicuously modified commercial devices - hams have been doing it since before "firmware" was even a word. The fact that it's replacing some code on a chip instead of a shunt resistor on a PCB really doesn't make a difference. And if this really was really the main issue, it seems pretty easy to just sign the firmware - I'm pretty sure many vendors do it already.
    - p_l 5y ago
      Vendors also want to comply with slightly different rules all over the world, and ultimately the easiest way becomes to sign and verify. The code being secret is more of "trade secrets" than anything legal.
p_l 5y ago
Exactly - the FCC certification is that a specific device, despite having purposeful (or accidental) transmitters, operates within the law and rules set by it for use of radio spectrum. The maker of the device is then able to sell it to people who are then indemnified should the device break those rules (and aren't required to have expensive in time and effort radio license themselves). With significant portion of the regulated behaviour being done in software, things can become a bit problematic if the end user can load any code they want. This is also why "BIOS whitelists" exist, as the certification applies to the whole radio equipment, which means the certification must cover the antenna - and those are built into laptops, meaning you can't certify the cards separately as their exact characteristics depend on the connected antennas.

So open firmware from the manufacturer is fine, but if you were to modify it and re-flash it yourself you would be breaking the law? I guess that makes sense, thanks for the clarification!

treesknees 5y ago

I don't think that makes sense at all. One major part of Part 15 from the FCC covers this. A device would fall under the category as an intentional radiator in part 15.1. And in part 15.23, considered a home-built device. § 15.23 Home-built devices. (a) Equipment authorization is not required for devices that are not marketed, are not constructed from a kit, and are built in quantities of five or less for personal use. (b) It is recognized that the individual builder of home-built equipment may not possess the means to perform the measurements for determining compliance with the regulations. In this case, the builder is expected to employ good engineering practices to meet the specified technical standards to the greatest extent practicable. The provisions of § 15.5 apply to this equipment. https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15 https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A... This entire part from the FCC basically states you don't need a license to operate in the frequencies for wifi, bluetooth, etc. You're not breaking a law by recompiling the firmware for your wifi module to fix a bug. You'd be breaking the law if you did so with the intention of operating within licensed spectrum/power levels, for example.

p_l 5y ago
The problem starts with the fact that the device doesn't have any way of showing that it was modified, and some of the frequencies involved are license-restricted (especially in 5GHz wifi bands - 2.4GHz is dumping ground free-for-all because of aircraft ovens anyway). So, let's say you modify something with your own firmware, break rules about ISM spectrum - or worse, mess with SDR hard enough you break some licensed spectrum, and upon investigation FCC certification marks are found and the number. Since certification points to vendor, vendor now has to explain why their device went outside of those limits, and might or might not be able to prove that you ran it with unlicensed firmware. So an obviously home build device will go under §15.23 easily, but inconspicuously modified commercially sold device won't - without possibly long court case, that is.
- franga2000 5y ago
  The FCC is very familiar with inconspicuously modified commercial devices - hams have been doing it since before "firmware" was even a word. The fact that it's replacing some code on a chip instead of a shunt resistor on a PCB really doesn't make a difference. And if this really was really the main issue, it seems pretty easy to just sign the firmware - I'm pretty sure many vendors do it already.
  - p_l 5y ago
    Vendors also want to comply with slightly different rules all over the world, and ultimately the easiest way becomes to sign and verify. The code being secret is more of "trade secrets" than anything legal.

p_l 5y ago

Exactly - the FCC certification is that a specific device, despite having purposeful (or accidental) transmitters, operates within the law and rules set by it for use of radio spectrum. The maker of the device is then able to sell it to people who are then indemnified should the device break those rules (and aren't required to have expensive in time and effort radio license themselves). With significant portion of the regulated behaviour being done in software, things can become a bit problematic if the end user can load any code they want. This is also why "BIOS whitelists" exist, as the certification applies to the whole radio equipment, which means the certification must cover the antenna - and those are built into laptops, meaning you can't certify the cards separately as their exact characteristics depend on the connected antennas.