Download packages and build.

Create directory tree

Create the following directory tree:

$ mkdir ~/sd410
$ cd ~/sd410

Download files from FTP site

Download the whole Ubuntu folder located in /dart-sd410/Software/ on Variscite FTP This will create the following directory tree

sd410
└── ubuntu
    ├── kernel
    └── ramdisk

NOTE:
Please refer to support@variscite.com for obtaining FTP credentials.

Download kernel source from git repository

$ git clone https://github.com/varigit/DART-SD410-kernel.git kernel
$ git checkout -b release/qcomlt-4.2

Build kernel source using supplied script file:

$ ./makebootimg.sh

The kernel sources will be built and the output boot image file will be created in the ~/sd410/ubuntu/Linaro4.2/ directory

Export Envornment variables for compiler and architecture

$ export CROSS_COMPILE=aarch64-linux-gnu-
$ export ARCH=arm64

The gcc-aarch64-linux-gnu package usually intalled by default. If it is not installed run

$ sudo apt-get install gcc-aarch64-linux-gnu

Select the needed defconfig file for kernel:

$ make O=build-${ARCH} defconfig

Build the kernel and modules

$ make O=build-${ARCH} -j10 
$ make O=build-${ARCH} INSTALL_MOD_PATH=build-${ARCH}-modules modules_install

Cycle power of the VAR-SD410CustomBoard with Back button pressed. it will enter fastboot. run the following commend to update the boot image:

$ sudo fastboot flash boot boot-sd410.img
$ sudo fastboot reboot

The board will update the system and reboot with the updated kernel