Here is how I did to install the OS (using MacOS)

1. Download image from Pine64.com or Pine64.org.
2. Format your Micro SD card using Disk Utility.
   
3. Launch terminal and list the available disk using diskutil command as below (we going to use disk2 base on the identifier):

   $ diskutil list
   /dev/disk0 (internal, physical):
      #:                       TYPE NAME                    SIZE       IDENTIFIER
      0:      GUID_partition_scheme                        *500.3 GB   disk0
      1:                        EFI EFI                     209.7 MB   disk0s1
      2:          Apple_CoreStorage Macintosh HD            499.4 GB   disk0s2
      3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   /dev/disk1 (internal, virtual):
      #:                       TYPE NAME                    SIZE       IDENTIFIER
      0:                  Apple_HFS Macintosh HD           +499.1 GB   disk1
                                    Logical Volume on disk0s2
                                    6D6E4910-AC62-4CC8-8F14-3A1227171470
                                    Unlocked Encrypted
   /dev/disk2 (internal, physical):
      #:                       TYPE NAME                    SIZE       IDENTIFIER
      0:     FDisk_partition_scheme                        *32.4 GB    disk2
      1:                 DOS_FAT_32 ROOT                    32.4 GB    disk2s1

4. Unmount the disk.

   $ diskutil unmountDisk /dev/disk2
   Unmount of all volumes on disk2 was successful

    

5. Unzip the downloaded image and burn the img file into disk.

   sudo dd if=/Users/dickson/Downloads/remix-v2.0-20160415-pine64-32GB.img of=/dev/disk2 bs=1m
   Password:

    

6. Upon burning successfull, you will see the message as below:

   $ sudo dd if=/Users/dickson/Downloads/remix-v2.0-20160415-pine64-32GB.img of=/dev/disk2 bs=1m
   Password:
   30255+0 records in
   30255+0 records out
   31724666880 bytes transferred in 47100.051106 secs (673559 bytes/sec)

7. Eject the disk if it still mounted.

   $ diskutil eject /dev/disk2
   Disk /dev/disk2 ejected

   p/s: For Windows user, you may format using Disk Management tool under [Control Panel\System and Security\Administrative Tools\Computer Management], and burn img file using Win32DiskImager. And if you feel the writing speed is too slow in MacOS, you may try using rdisk instead of disk, as they using different write mechanism.

   UPDATED : Just found this handy GUI tool etcher.io to burn image.
   

Credit to : rayhightower.com && www.hostvirtual.com && serenity.ee