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+# Zephyr Proof-of-Concept-Device Bringup
+
+It may be useful to build a Zephyr OS-based EC for a device which
+already has a CrOS EC device build, for the purposes of demonstrating
+the feasibility of Zephyr OS.
+
+This document is a work-in-progress list of tricks & tools that may be
+useful to you.
+
+## Initial Bringup
+
+Initially, you'll want to get a basic UART functioning with nothing
+but a shell and some basic console commands.
+
+An example CL to do this for Lazor can be found
+[here](https://crrev.com/c/2749765).
+
+## Bringing up GPIOs
+
+After you have UART functioning, GPIOs can be an easy target to start
+unblocking further features.
+
+We have a very ugly program to auto-generate the GPIO DTS based on
+gpio.inc for the existing board.  You can find it at
+`util/gpios_to_zephyr_dts.c`, and instructions are in the file on how
+to compile and use it.  You may have to hand-modify the output.
+
+The resultant CL for Lazor can be found [here](https://crrev.com/c/2749768).
+
+## Bring up Host Commands
+
+Set `CONFIG_PLATFORM_EC_HOSTCMD=y` and enable the appropriate
+host-command interface for your platform (e.g., eSPI).
+
+An example CL for Lazor can be found [here](https://crrev.com/c/2749428).
+
+As long as you get this compiling that should be enough to move to the
+next step.  Further testing of the host command layer will require
+power sequencing up and going.
+
+## Enabling some simple GPIO-based buttons and switches
+
+Next, you can:
+
+* [Add the lid switch](https://crrev.com/c/2749768)
+* [Add the power button](https://crrev.com/c/2749426)
+* [Add AC presence detection](https://crrev.com/c/2749428)
+
+## Power Sequencing
+
+TODO(jrosenth): add steps on enabling power sequencing and expand this
+document.