Merge "getting-started: Add a section on machine prereqs"
diff --git a/DeviceTreeOverlays.md b/DeviceTreeOverlays.md
new file mode 100644
index 0000000..f1ae8a7
--- /dev/null
+++ b/DeviceTreeOverlays.md
@@ -0,0 +1,60 @@
+# Device tree overlays
+
+The uboot script on Mendel is configured to load device tree blob (`.dtb`) files from `/boot/` and
+overlay the existing device tree with any `dtb` files specified in the `/boot/overlays.txt` file.
+
+For example, you can use the following steps to increase the CMA size to 512 MiB
+(default is 320 MiB). (All steps are performed on your Mendel device.)
+
+First, create your device tree source (`.dts`) file (in this example, named `cma512.dts`):
+
+```
+// Set CMA region to 512M
+/dts-v1/;
+/plugin/;
+
+/ {
+    compatible = "fsl,imx8mq-phanbell";
+
+    fragment@0 {
+        target-path = "/";
+        __overlay__ {
+            reserved-memory {
+                linux,cma {
+                    size = <0 0x20000000>;
+                };
+            };
+        };
+    };
+};
+```
+
+Install the device tree compiler:
+
+```
+sudo apt-get update
+
+sudo apt-get install device-tree-compiler
+```
+
+Compile your `dts` file to `dtb` format:
+
+```
+dtc -I dts -O dtb -o cma512.dtbo cma512.dts
+```
+
+Move the `cma512.dtbo` file into `/boot/` and edit the `/boot/overlays.txt` file (as root) to
+include this new file. The `overlays.txt` file should then look like this:
+
+```
+# List of device tree overlays to load. Format: overlay=<dtbo name, no extenstion> <dtbo2> ...
+overlay=cma512
+```
+
+Then reboot and you're done. You can verify the CMA update like this:
+
+```
+cat /proc/meminfo | grep CmaTotal
+```
+
+It should print `524288 kB`.
\ No newline at end of file
diff --git a/ReadMe.md b/ReadMe.md
index e6303af..834d746 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -1,10 +1,15 @@
 # What is Mendel Linux?
 
 Mendel Linux is a lightweight derivative of Debian Linux that runs on a number
-of Coral development boards, including the Coral EdgeTPU.
+of Coral development boards, such as the
+[Dev Board](https://coral.ai/products/dev-board/) and
+[SoM](https://coral.ai/products/som/).
 
 If you're looking to get started with any of the Coral boards, please take a
-look at the [Coral Website](https://coral.withgoogle.com) for more information.
+look at the [Coral doccumentation](https://coral.ai/docs) for more information.
+
+If you want to know what's changed in Mendel, see our
+[release notes](https://coral.googlesource.com/docs/+/refs/heads/master/Releases.md).
 
 If you're looking to get started developing, patching, or building Mendel for
 your own uses, please read our [Getting Started
@@ -34,16 +39,18 @@
 To build an image from our tooling for one of our boards, check out [Getting
 Started
 documentation](https://coral.googlesource.com/docs/+/refs/heads/master/GettingStarted.md)
+
 Note: we generally discourage this, as we put a great deal of effort into making
 sure our releases run well on the boards we target. Mendel is a proper Linux
 distribution: we work with packages, not images, and any image should be
 possible to upgrade to the latest release with a simple `apt-get dist-upgrade`
-without requiring a reboot (modulo kernel and bootloader updates, obviously).
+without requiring a reboot (modulo kernel and bootloader updates, obviously,
+which require [reflashing the board](https://coral.ai/docs/dev-board/reflash/)).
 
 ## What do we support?
 
-Mendel currently only supports the Coral EdgeTPU Dev Board (also known as
-enterprise, or phanbell).
+Mendel currently only supports the Coral Dev Board (also known as
+enterprise, or phanbell) and SoM.
 
 For development, our build system only currently supports Linux systems.
 Unfortunately, this is due to various factors out of our control, so it is
diff --git a/ReleaseProcess.md b/ReleaseProcess.md
deleted file mode 100644
index 6580e82..0000000
--- a/ReleaseProcess.md
+++ /dev/null
@@ -1,35 +0,0 @@
-# Release Process
-
-1. Update all or some of the package version numbers
-   - All of the package changelogs need to have the proper release listed in the
-     changelog after the package number.
-2. Create the release branch in all projects
-3. Create the release branch in continuous-build
-   - Add branch=release-$RELEASE for all projects in .gitmodules
-   - git submodule update --remote --init
-   - git add -A; git commit
-   - git push origin HEAD:refs/heads/release-$RELEASE
-4. All package repositories we have updated need to have git tags
-   - Format of the tag is the same as the package version in the
-     debian/changelog file.
-   - git tag $VERSION aiy/release-$RELEASE
-   - If the package has separate sources in another repo, you need to tag the
-     same way in the source repo.
-   - git push --tags aiy
-5. Make a new release candidate for the appropriate release
-   - If no proposals exist for the release, create a new Rollup proposal and
-     approve it.
-6. Tag the latest rapture with the $RELEASE tag.
-   - rapture --universe cloud-apt settag mendel-core-unstable spacepark-eng.$RELEASE:true
-7. Run the kokoro job for $RELEASE.
-
-Cherry picks:
-1. Commit to master
-2. Cherry pick to next branch
-3. All packages we have updated need to have tags
-4. Checkout $current-release in continuous
-5. `git submodule update --remote --init`
-6. Check status, update git submodules, commit
-7. Run the rapid release job on for $current-release
-   - Looks at the next branch looking for the latest versions and updates that way
-8. Tag the latest rapture with the next tag.
diff --git a/Releases.md b/Releases.md
new file mode 100644
index 0000000..04c8f7f
--- /dev/null
+++ b/Releases.md
@@ -0,0 +1,43 @@
+# Mendel release notes
+
+This is a non-exhaustive summary of changes included in each version of Mendel.
+
+To check your Mendel version, run `cat /etc/mendel_version`.
+
+For system image downloads, see [coral.ai/software](https://coral.ai/software/).
+
+
+## 4.0 (day)
+
++   First release based on [Debian 10 (buster)](
+    https://www.debian.org/releases/buster/arm64/release-notes/ch-whats-new.en.html)
+    (Note that our distribution does not include everything from Debian;
+     for example, Mendel does not include desktop environments and applications,
+     because our system is designed for embedded systems. Also, the
+     new SecureBoot and AppArmor changes do not apply to Mendel)
++   Support for Python 3.7
++   Support for OpenCV and OpenCL
++   Support for device tree overlays
++   Upgraded GStreamer pipelines
++   Upgraded Linux Kernel (4.14)
++   Upgraded U-Boot bootloader (2017.03.3)
+
+
+## 3.0 (chef)
+
++   First open source release
++   First release with the Mendel Development Tool (MDT)
++   Improved security for SSH authentication
+
+
+## 2.0 (beaker)
+
++   Resolved Hynix/Micron memory timing stability
++   Support for USB-C connections in U-Boot
++   Support for Mac in flash.sh script
++   Released edgetpu_demo for out-of-box Edge TPU demo
+
+
+## 1.0 (alpha)
+
+Our first Mendel release!
\ No newline at end of file