Advanced Embedded Controller Mods

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1

What kinds of features can be hacked onto a ChromeOS device by modifying the Embedded Controller firmware?
For instance, would it be possible to add laptop-style battery managment (SMbus?) to wall-powered devices (Chromeboxes, Chromebits and Chromebases) by modifying the EC firmware and breaking out some GPIO pins?

I’ve wanted to build a laptop around a Chromebox during the last few months, but don’t want to settle for USB-PD PowerBanks.

  • Can’t view their remaining capacity on your host device, so you have to rely on the PB’s status LCD (makes it impossible to tuck it away in a corner)
  • Don’t want to occupy a valuable I/O port, or lose power because the host’s USB stack did a mistake (both of these can probably be mitigated by plugging the PB into the traditional barrel jack through an adapter)

I’m not a programmer or electronics engineer (I don’t even have a Chrome device to test with) - I’m just disappointed that 90% of firmware/coreboot discourse revolves around security, OS compatibility and efficiency.

2

Accessing free pins on the EC would be quite tricky to do something like this. Maybe battery management would be better left for some extra microcontroller you add yourself.

3

Yeah, I figured pushing battery management through the EC instead of a little USB gadget might be a bit hamhanded.

That said, I’m still curious about what the EC can do and how much power/authority it has over the system - maybe put a footnote on it in the FAQ.
I recall the CCC talk only mentioned RGB, fan control and the fact that Librebooted Thinkpads/Elitebooks/Latitudes still rely on proprietary EC firmware.

(I actually considered tagging this thread topic as site feedback.)

4

What the EC can do depends on the device. On a laptop it obviously has more capabilities such as the keyboard and the various buttons/switches.