How do the kill switches work?

[Arwen]

If this does not answer your questions, please ask more here, so we can add them to the Wiki;

Wiki - Pinebook Pro - Privacy Switches

Well, to restate:

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• The wiki states that the "power" (kill switch) state is stored across reboots.  Where is it stored?  
  
  As an example as to why this is relevant, all Chromebooks have a similar feature: a "developer mode" switch that disables the secure boot process, allowing unsigned software to be loaded onto them. In most commercially-available Chromebooks, this switch is virtualized, with the switch state stored in RAM backed by the laptop's primary battery.  Thus, the switch state is persisted across reboots -- unless the laptop's battery is discharged completely.  When that happens, the RAM is cleared, and the virtual devmode switch is effectively cleared with it.
  
  
• (I've pretty much managed to answer this one myself.) The keyboard's main connection is USB. (Incidentally,  AIUI, all USB keyboards are USB 1.1, not USB 2.0.)  Since USB has no facility for privacy switches, it must also have a secondary connection to signal that a kill switch should be enabled/disabled.  Where on the schematics can I find this connection?
  
  I've found, on page 20 of the mainboard schematics, I'm pretty sure U23 (labeled as "SH68F83Q") is involved, because has connections labeled MIC_CUT, WIFI_CUT, and CAM_CUT.  There's also an entry here https://wiki.pine64.org/index.php/Pinebo...eripherals  under "Keyboard Information" to a "Sinowealth SH68F83 [no Q] Datasheet".  This link is dead, it goes to a blank page.
  
  I'm guessing that this might be what the keyboard is physically wired into; I've seen that 'R' and 'C' column before, but on a much smaller scale (3-by-4).  Is that accurate?
  

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For the first, I've updated the Wiki to indicate it's stored in the keyboard's flash memory.

On the second, @pfeerick added the PDF to our Wiki and corrected the link.

So, 2 things improved.

One note, Jack's keyboard firmware can send a special key sequence on disable and enable of the kill switches. This is to allow future OS level detection of change, like re-enabling WiFi chip. It's still early days, so we will have to see if Jack's firmware becomes the "new" default firmware. Already we have seen a change in the default OS from Debian to Manjaro.