You can create builds for Nexus devices using Android Open Source Project (AOSP) builds and the relevant hardware-specific binaries. For available Android builds and targeted devices, see Source Code, Tags, and Builds.

You can also create builds for HiKey Android reference boards, which are designed to help non-Nexus component vendors develop and port drivers to Android releases. Using a reference board can ease upgrade efforts, reduce time-to-market for new Android devices, lower device costs by enabling ODM/OEMs to choose from a wider range of compatible components, and increase the speed of innovation among component suppliers.

Google supports HiKey960 and HiKey certified 96Boards as Android reference boards. AOSP provides kernel source and board support for HiKey so developers can easily create and debug new and existing peripheral drivers, do kernel development, and perform other tasks with fewer OEM encumbrances. To develop new ContextHub features that use new sensors or LEDs, you can also use a Neonkey SensorHub connected to a HiKey or HiKey960 development board.

HiKey960 boards

The HiKey960 board is available in a 3GB RAM configuration from LeMaker (via Amazon.com) and from Lenovator.

Additional resources:

• HiKey960 schematics
• HiKey960 user guide
• 96boards wiki

Use the following commands to download, build, and run Android on the HiKey960 board.

Compiling userspace

1. Download the Android source tree:

   repo init -u https://android.googlesource.com/platform/manifest -b master
   repo sync -j24
   

2. Download and extract binaries into the Android source tree:

   wget https://dl.google.com/dl/android/aosp/arm-hikey960-OPR-cf4e0c80.tgz
   tar xzf arm-hikey960-OPR-cf4e0c80.tgz
   ./extract-arm-hikey960.sh
   

3. Build:

   . ./build/envsetup.sh
   lunch hikey960-userdebug
   make -j32
   

Installing initial images

1. Select fastboot mode turning ON switch 1 and 3 (for details, refer to the HiKey960 user guide).
2. Power the board.
3. Flash initial images:

   cd device/linaro/hikey/installer/hikey960
   ./flash-all.sh
   

4. Turn OFF switch 3 and power cycle the board.

Flashing images

1. Enter fastboot mode by turning ON switch 1 and 3.
2. Flash images by running the following commands:

   fastboot flash boot out/target/product/hikey960/boot.img
   fastboot flash dts out/target/product/hikey960/dt.img
   fastboot flash system out/target/product/hikey960/system.img
   fastboot flash cache out/target/product/hikey960/cache.img
   fastboot flash userdata out/target/product/hikey960/userdata.img
   

3. Turn OFF switch 3 and power cycle the board.

Building the kernel

1. Run the following commands:

   git clone https://android.googlesource.com/kernel/hikey-linaro
   cd hikey-linaro
   git checkout -b android-hikey-linaro-4.9 origin/android-hikey-linaro-4.9
   make ARCH=arm64 hikey960_defconfig
   make ARCH=arm64 CROSS_COMPILE=aarch64-linux-android- -j24
   

2. Update the kernel in the boot image.
   • Copy hi3660-hikey960.dtb (arch/arm64/boot/dts/hisilicon/hi3660-hikey960.dtb) to the hikey-kernel directory as file: hi3660-hikey960.dtb-4.9
   • Copy the Image file (arch/arm64/boot/Image.gz) to the hikey-kernel directory as file: Image.gz-hikey960-4.9
3. Make the boot image:

   make bootimage -j24
   

Setting serial number

To set random serial number, run:

fastboot getvar nve:SN@16_DIGIT_NUMBER

Bootloader exports the generated serial number to kernel via androidboot.serialno=.

Setting monitor resolution

Edit the device/linaro/hikey/hikey960/BoardConfig.mk parameter BOARD_KERNEL_CMDLINE and configure the video setting. Example setting for a 24" monitor is video=HDMI-A-1:1280x800@60.

HiKey boards

The HiKey board (also known as HiKey620) is available in 1GB RAM and 2GB RAM configurations from Lenovator:

Additional resources:

• HiKey schematics
• HiKey user guide
• 96boards wiki

Use the following commands to download, build, and run Android on the HiKey board.

Compiling userspace

1. Download the Android source tree:

   repo init -u https://android.googlesource.com/platform/manifest -b master
   repo sync -j24
   

2. Download and extract HDMI binaries into the Android source tree:

   wget https://dl.google.com/dl/android/aosp/linaro-hikey-20170523-4b9ebaff.tgz
   tar xzf linaro-hikey-20170523-4b9ebaff.tgz
   ./extract-linaro-hikey.sh
   

3. Install mcopy utility:

   apt-get install mtools
   

4. Build:

   . ./build/envsetup.sh
   lunch hikey-userdebug
   make -j32
   

Note: For 4GB eMMC, instead of $ make -j32 use: $ make -j32 TARGET_USERDATAIMAGE_4GB=true.

Installing initial fastboot and ptable

1. Select special bootloader mode by linking J15 1-2 and 3-4 pins (for details, refer to the HiKey user guide).
2. Connect USB to PC to get ttyUSB device (ex: /dev/ttyUSB1).
3. Power the board:

   cd device/linaro/hikey/installer/hikey
   ./flash-all.sh /dev/ttyUSB1 [4g]
   

4. Remove jumper 3-4 and power the board.

Flashing images

1. Enter fastboot mode by linking J15 1-2 and 5-6 pins.
2. Run the following commands:

   fastboot flash boot out/target/product/hikey/boot.img
   fastboot flash -w system out/target/product/hikey/system.img
   

3. Remove jumper 5-6 and power the board.

Building the kernel

1. Run the following commands:

   git clone https://android.googlesource.com/kernel/hikey-linaro
   cd hikey-linaro
   git checkout -b android-hikey-linaro-4.9 origin/android-hikey-linaro-4.9
   make ARCH=arm64 hikey_defconfig
   make ARCH=arm64 CROSS_COMPILE=aarch64-linux-android- -j24
   

2. Copy output to the hikey kernel directory (/kernel/hikey-linaro):
   • Copy hi6220-hikey.dtb (arch/arm64/boot/dts/hisilicon/hi6220-hikey.dtb) to the hikey-kernel directory as file hi6220-hikey.dtb-4.9.
   • Copy the Image file (arch/arm64/boot/Image-dtb) to the hikey-kernel directory as file Image-dtb-4.9.
3. Make the boot image:

   make bootimage -j24
   

Setting monitor resolution

Edit device/linaro/hikey/hikey/BoardConfig.mk parameter BOARD_KERNEL_CMDLINE and configure the video setting. Example setting for a 24" monitor: video=HDMI-A-1:1280x800@60.

Configuring kernel serial output (uart3)

Set the J2 low speed expansion connector to 1 - Gnd, 11 - Rx, 13 - Tx. For details, refer to the HiKey user guide.

Neonkey SensorHub

To develop new ContextHub features that use new sensors or LEDs, you can use Neonkey SensorHub connected to a Hikey or Hikey960 development board.

Neonkey is a certified 96Boards mezzanine base on STM32F411CE with the following components:

• Pressure sensor: BMP280
• ALS/Proximity sensor: RPR-0521RS
• ARM Hall sensor: MRMS501A
• LED driver with 15 LEDs: LP3943
• Accel/Gyro + Geomagnetic sensors: BMI160 + BMM150
• Temp/Humidity sensor: SI7034-A10
• 4 GPIO-driven LEDs, I2C expansion, GPIO (2 lines) expansion, JTAG connector
• NOR Flash: 512KB
• SRAM: 128 KB, 96boards LS Expansion connector

Kernel source and ContextHub board support is available in AOSP to help developers create and debug new sensors, make new HAL and kernel changes, etc. with fewer OEM encumbrances.

To build, enable, and upload Neonkey:

1. Pull AOSP source:

   repo init -u https://android.googlesource.com/platform/manifest -b master & repo sync -j24
   

2. Build:

   . ./build/envsetup.sh
   lunch hikey-userdebug
   . device/google/contexthub/firmware/toolchain-setup.sh
   make -C device/google/contexthub/firmware/variant/neonkey
   adb push device/google/contexthub/firmware/out/nanohub/neonkey/full.bin /data/local/tmp
   

3. To enable Neonkey, enter boot mode using the following method:
   1. Connect BOOT0 to 1V8 (link JTAG P4 1-5 pins)
   2. Hold USR button
   3. Push RST button
4. To upload the firmware:

   adb root
   adb shell stm32_flash -u -d /dev/ttyAMA2 -e 0xffff -w /data/local/tmp/full.bin
   

5. To build userspace HAL:

   make TARGET_SENSOR_MEZZANINE=neonkey -j24
   fastboot flashall