Identify the SD Card - Flashing an SD card is quite straight forward with Mac OS X. Start by pressing CMD SPACE to reveal the Spotlight search bar at the top right hand side of the screen. In this search bar, type terminal and press return to launch the Terminal application.

1. Insert the SD card into your Mac’s SD card drive.

To find the connected SD card, in the terminal window type:

diskutil list

2. Make a note of the identity of yours. In my example it is /dev/disk2 but yours may be different.

If the SD card was automatically mounted, as mine way, you will need to unmount it with the following command in Terminal. Remember to correctly identify your SD card if it is a different number to my example.

diskutil unmountdisk /dev/disk2

Navigate to the location that you downloaded and extracted the .img file from the .zip download. In my case it is the Downloads directory.

cd Downloads/

TIP: The dd command is very powerful and you risk serious corruption to your Mac if you use it incorrectly. Triple check your command before executing it, or use a different method (described below) to flash your SD Card if in doubt.

Flash the SD Card

Ensuring that you replace the .img and destination, in my example, with the correct .img name destination disc for yours, enter the following command:

sudo dd if=2013-07-26-wheezy-raspbian.img of=/dev/disk2 bs=2m

It will then take a few minutes to flash the SD card during which time no progress information will be shown. Be patient. On completion, you will get a confirmation with some information displayed in terminal.

You are now free to unmount the SD card for use in your Raspberry Pi.