Create Bootable SD Card
This section show how to install the Debian operating system that is bootable from the SD Card to your HiKey on a Linux host computer.
Step 1: Make sure you have the latest bootloader flashed:
Step 2: Download SD Card Image
- Download 
$ wget http://snapshots.linaro.org/96boards/hikey/linaro/debian/latest/linaro-stretch-developer-hikey-*.sd.gz -O linaro-stretch-developer-hikey.sd.gz - Decompress 
$ gunzip linaro-stretch-developer-hikey.sd.gz 
Step 3: Flash image to SD Card
- Remove SD card from host computer and run the following command: 
$ lsblk - Note all recognized disk names
 -  Insert SD card and run the following command (again): 
$ lsblk - Note the newly recognized disk. This will be your SD card.
 - Remember your SD card device name
 - Flash SD card 
$ dd if=linaro-stretch-developer-hikey.sd of=/dev/xxx status=progressNOTE: /dev/xxx is the device name of you sdcard
 
Step 4: Boot HiKey from SD Card
- Make sure the HiKey is Powered OFF
 - Insert SD Card into HiKey
 - Power On
 - Hikey should now boot Debian from SD Card
 
NOTE: SD Card is the first boot preference, It will always boot irrespective of ANY OS flashed on the eMMC