1. Android build
  - Download original android source code ( android-12.0.0_r11 ) from http://source.android.com   
  ( $repo init -u https://android.googlesource.com/platform/manifest -b android-12.0.0_r11
    $repo sync -cdq -j12 --no-tags
    $repo start android-12.0.0_r11 --all 
  )
  - And, 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_S.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

   a)cd android	 

a)make -C kernel-4.19 O=../out ARCH=arm CC=../prebuilts/clang/host/linux-x86/clang-r383902/bin/clang CLANG_TRIPLE=arm-linux-gnueabi- CROSS_COMPILE=../prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.9/bin/arm-linux-androidkernel- LGE_TARGET_PLATFORM=mt6765 LGE_TARGET_DEVICE=meh15lm LGE_LAMP_DEVICE=yes MTK_DTBO_FEATURE=yes PLATFORM_DTB_NAME=mt6762 PROJECT_DTB_NAMES=muse6762_eh15_s muse6762_eh15_s_debug_defconfig 
b)make -C kernel-4.19 O=../out ARCH=arm CC=../prebuilts/clang/host/linux-x86/clang-r383902/bin/clang CLANG_TRIPLE=arm-linux-gnueabi- CROSS_COMPILE=../prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.9/bin/arm-linux-androidkernel- LGE_TARGET_PLATFORM=mt6765 LGE_TARGET_DEVICE=meh15lm LGE_LAMP_DEVICE=yes MTK_DTBO_FEATURE=yes PLATFORM_DTB_NAME=mt6762 PROJECT_DTB_NAMES=muse6762_eh15_s headers_install
c)make -j16 -C kernel-4.19 O=../out ARCH=arm CC=../prebuilts/clang/host/linux-x86/clang-r383902/bin/clang CLANG_TRIPLE=arm-linux-gnueabi- CROSS_COMPILE=../prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.9/bin/arm-linux-androidkernel- LGE_TARGET_PLATFORM=mt6765 LGE_TARGET_DEVICE=meh15lm LGE_LAMP_DEVICE=yes MTK_DTBO_FEATURE=yes PLATFORM_DTB_NAME=mt6762 PROJECT_DTB_NAMES=muse6762_eh15_s

* "-j16" : The number, 16, is the number of multiple jobs to be invoked simultaneously. 
- After build, you can find the build image(Image.gz) at out/arch/arm/boot.

