"Privacy" DIP switch wiring - real or software?

[cndg]

How are the DIP switches physically wired?  Is there a PCB diagram to prove that they're not just a software trick?

The reason I ask, is that other smartphone vendors have made "hardware privacy claims" that have, many times, proven to be lies... such as cameras with LEDs (except the camera can still be enabled without the LED illuminating) and "sub-dermal blah blah" about fingerprint sensors (which were still bypassed with a gummy bear), and those are just the tip of the iceberg, because about 99% of all "security" claims are never actually verified.  Stick a "printf()" inside the gnupg/openssl/etc prng "seed" function (the code that bypasses system entropy) to see what I mean...

[kqlnut]

You can find the schematics for the PinePhone at least in the wiki (no PCB files though). Look for "SW1-[A-F]", those should be the kill switches.
It looks to me like:
- SW1-A cuts off the modem's power system
- SW1-B disables the WIFI/BT module (assuming that the chip is disabled if CHIP_EN is pulled down)
- SW1-C disables MICBIAS; I think the mic might still work in this case, but with barely audible volume. If that is really the case, it would be a security flaw in my opinion, but it should be tested before making assumptions. Maybe the mic doesn't work at all without the bias voltage.
- SW1-D and SW1-E cut power to the rear and front camera sensors respectively
- SW1-F connects to an analog switch which switches between headphone out R/L (open) and serial TX/RX (closed)

I'm guessing that the schematics for the PinePhone Pro will be made available too. Probably it will not be too different in regards to the kill switches.

[cndg]

This post suggests the mic-kill switch is not reliable: https://forum.pine64.org/showthread.php?tid=14353

Has anyone checked their PCB? Do the real switches match what they tell us they do?

[Ulfnic]

I asked a similar question about the Pinebook Pro a while back and they got back to me very quickly:

"The keyboard firmware which include privacy switch can be update thru utility, please check out: https://github.com/ayufan-rock64/pineboo...rd-updater

Please note that the ARM CPU on Pinebook Pro cannot directly control/overwrite the privacy switch.

Regards,

Support team #1"

Someone would need to email support to verify this but i'd guess the Pinephone similarly asks a chip to turn hardware on/off rather than breaking the connection directly and this chip can probably be written to from the operating system so technically someone with a lot of Pinephone know-how and the ability to run something with root privileges on your phone could turn these back on.

I can't speak to why these aren't direct kill switches but here's my guess:
- Cutting power suddenly could cause software problems and the devs already have their hands full.
- Returning power suddenly could cause voltage drops.
- It may be considerably complex within the provided space to route direct power to the dip switches.

That I know of... there isn't a phone or laptop that exists with absolute/direct power off kill switches. That said... i'd like one