To build the VIMs SDK source code, you need to install the extra toolchains for cross-compiling:
1. The following software packages of Ubuntu 16.04 (64-bit) shall be installed for compiling Android
$ sudo apt-get update $ sudo apt-get install openjdk-8-jdk automake make git gperf zip dos2unix bison perl gcc g++ tig pkg-config cpp-aarch64-linux-gnu $ sudo apt-get install unzip lib32z1 libx11-dev lib32z-dev ccache gitk xmllint libxml2-utils libssl-dev
2. Toolchains for U-Boot
$ sudo mkdir /opt/toolchains $ cd /opt/toolchains $ wget https://dl.khadas.com/products/vim4/tool/gcc-linaro-7.3.1-2018.05-i686_aarch64-elf.tar.xz $ wget https://dl.khadas.com/products/vim4/tool/xpack-riscv-none-embed-gcc-8.3.0-1.2-linux-x64.tar.gz $ sudo tar -xvJf gcc-linaro-7.3.1-2018.05-i686_aarch64-elf.tar.xz -C /opt/toolchains $ sudo tar -zxvf xpack-riscv-none-embed-gcc-8.3.0-1.2-linux-x64.tar.gz -C /opt/toolchains
3. Toolchains for the Linux kernel
$ sudo apt-get install gcc-4.8-aarch64-linux-gnu
The main toolchain for the Linux kernel is provided in the SDK prebuilts/clang/host/linux-x86/clang-r383902/bin.