1. Android build
  - Download original android source code ( android-10.0.0_r15 ) from http://source.android.com
  ( $repo init -u https://android.googlesource.com/platform/manifest -b android-10.0.0_r15
    $repo sync -cdq -j12 --no-tags
    $repo start  android-10.0.0_r15 --all
  )
	   
  - Then, merge the source into the android source code
  - Run following scripts to build android
    a) source build/envsetup.sh
    b) lunch 1
    c) make -j4
	
	
  - When you compile the android source code, you have to add google original prebuilt source(toolchain) into the android directory.
  - After build, you can find output at out/target/product/generic

2. Kernel Build  
  - Uncompress using following command at the android directory

    a) tar -xvzf *_Kernel_Q.tar.gz

  - When you compile the kernel source code, you have to add google original "prebuilt" source(toolchain) into the android directory.
  - Run following scripts to build kernel
  
   1. cd kernel/msm-4.4
   2. echo CONFIG_USB_HOST_NOTIFY=y >> arch/arm64/configs/phoenix_sb_jp-perf_defconfig
   3. export CROSS_COMPILE=../../../prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin/aarch64-linux-android- 
   4. make ARCH=arm64 O=./out phoenix_sb_jp-perf_defconfig
   5. make ARCH=arm64 O=./out KERNEL_COMPRESSION_SUFFIX=gz

      - After build, you can find the build image(zImage) at kernel/msm-4.4/out/arch/arm64/boot

 