Android Source web site.
You'll need to Download the Pixel C specific drivers (Pixel C binaries for Android 7.0.0), select one of the aosp_dragon-* lunch targets, build it, flash it, and it should run.
Of course, the AOSP provides a binary version of the Pixel C kernel image (device/google/dragon-kernel/Image.fit) used in the boot image you just built.
But if you want to build your own kernel, here are a few tips I had to experiment myself in order to test a few kernel patches on the Pixel C.
For the sake of this post, we'll use the official Android kernel tree for NVIDIA Tegra SoC familly that you can git clone here:
$ git clone -b android-tegra-dragon-3.18-nougat https://android.googlesource.com/kernel/tegraThe easiest way is to build your kernel while your environment is setup for the AOSP build. You'll have the aarch64 compilers and binutils in your path.
$ source ./build/envsetup.shThen go to the kernel root folder and export the cross compilation build variables:
$ lunch aosp_dragon-userdebug
$ export ARCH=arm64Create the kernel config file:
$ export CROSS_COMPILE=aarch64-linux-androidkernel-
$ make dragon_defconfigAnd Build your kernel image:
$ make -jXThe uncompressed kernel image is located here: arch/arm64/boot/Image
This is the image we will use to create the Image.fit file used by the AOSP build. FIT stands for Flattened Image Tree and contains one or more kernel images along with various DTBs (Device Tree Blob). You'll need mkimage from the u-boot-tools package to create the FIT file from an ITS file (Image Tree Source).
The Pixel C bootloader seems to want lz4 compressed images only so we will have to make it:
$ lz4c ./arch/arm64/boot/Image Image.lz4Now it's time to create the FIT image that will contain the freshly compiled kernel Image and the device tree blob for the Pixel C. The dts files are compiled by the kernel build system and stored in the same folder. The dtb for the Pixel C is arch/arm64/boot/dts/tegra/tegra210-smaug-p1.dtb.
Create the its file (Let's call it Image.its). As it is intended to boot on the Pixel C only, it will contain the image and one ftd entry.
* Simple U-Boot uImage source file containing a
* single kernel and FDT blob
description = "Simple image with single Linux kernel and FDT blob";
#address-cells = <1>;
description = "Tegra Dragon Linux kernel";
data = /incbin/("./Image.lz4");
type = "kernel_noload";
arch = "arm64";
os = "android";
compression = "lz4";
description = "Flattened Device Tree blob";
data = /incbin/("./arch/arm64/boot/dts/tegra/tegra210-smaug-p1.dtb");
type = "flat_dt";
arch = "arm64";
compression = "none";
algo = "sha1";
default = "conf@1";
description = "Boot Linux kernel with FDT blob";
kernel = "kernel@1";
fdt = "fdt@1";
Build the FIT image:
$ mkimage -f Image.its Image.fitNow copy Image.fit to AOSP_ROOT/device/google/dragon-kernel and rebuild the bootimage from the AOSP root:
$ make bootimageReboot the Pixel C in fastboot mode and flash the boot image:
$ fastboot flash bootThat's it! Reboot your device and voilà!