The first thing you have to do is download the img file, you can download the last Ubuntu version for Odroid on the Odroid Wiki.
There are 2 versions one with mate desktop and another minimal installation (the minimal doesn't install a desktop).
You also can download the md5sum to check the integrity of the downloaded file.
Extract the file
To flash ubuntu on the sd card we are going to use Disk Destroyer (dd), is already included on OS X. Be careful it will erase everything on your sd card and the new format will be EXT4 so you will need drivers to read the sd card after flash the card, but that is optional.
Before to start we have to unmount the sd card.
If you don't know where is the sd card you can use this command:
The output is something similar to this:
/dev/disk0 (internal): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme 500.3 GB disk0 1: EFI EFI 314.6 MB disk0s1 2: Apple_CoreStorage Macintosh HD 499.3 GB disk0s2 3: Apple_Boot Recovery HD 650.0 MB disk0s3 /dev/disk1 (internal, virtual): #: TYPE NAME SIZE IDENTIFIER 0: Macintosh HD +498.9 GB disk1 Logical Volume on disk0s2 Unencrypted /dev/disk2 (external, physical): #: TYPE NAME SIZE IDENTIFIER 0: FDisk_partition_scheme *64.0 GB disk2 1: Windows_FAT_16 BOOT 67.1 MB disk2s1 2: Linux Untitled 64.0 GB disk2s2
My sd card is disk2. By default OS X mounts the disk, the command to unmount the drivers is diskutil:
diskutil unmountDisk /dev/disk2
Once the memory is unmounted we can flash the img image in the sd card with this command:
sudo dd if=<my/odroid/image.img> of=</dev/path/of/card> bs=1m
sudo dd if=/Users/wdiaz/Downloads/ubuntu-16.04-minimal-odroid-xu3-20160706.img of=/dev/disk2 bs=1m
If all is correct the output will be similar to this:
1947+0 records in 1947+0 records out 2041577472 bytes transferred in 180.054660 secs (11338654 bytes/sec)
Now you can unmount the sd card again and use it in you Odroid.
User: odroid, root