Using OS X to validate a Raspbian image and write it to an SD card

If you are a Mac user, the process will be a little different from the Windows recipe, but still not too difficult. To do it, we'll leverage OS X's built-in *nix system tools.

Note

Mac OS X used to have a lot of options for easy GUI image writers, but many of them were not updated over time. After Yosemite 10.10.5, the Raspberry Pi community recommends using command-line tools. Fortunately, it is a pretty easy process.

How to do it...

The process for validating and copying a NOOBs installation on OS X is fairly straightforward:

1. Open a Terminal window in OS X.
2. Next, run shasum against the downloaded ZIP file to validate the signature:

   $ shasum ~/Downloads/2016-05-27-raspbian-jessie.zip 
   64c7ed611929ea5178fbb69b5a5f29cc9cc7c157
       /Users/ed/Downloads/2016-05-27-raspbian-jessie.zip
   

   

   The Raspbian Jessie download and SHA-1 signature

3. If the return value matches the SHA-1 signature provided on the Raspberry Pi downloads page, your file is good and can be unzipped:

   Note

   As the downloads change, the SHA-1 will change too, so you'll likely be comparing a different number to your shasum output.

   $ unzip ~/Downloads/2016-05-27-raspbian-jessie.zip 
   Archive:  /Users/ed.snajder/Downloads/2016-05-27-
       raspbian-jessie.zip
   inflating: 2016-05-27-raspbian-jessie.img  
   

4. Next, look at the filesystem before inserting the SD card:

   $ df -h
   Filesystem      Size   Used  Avail Capacity  iused 
       ifree %iused  Mounted on
   /dev/disk1     232Gi  216Gi   16Gi    94% 56751574 
       4163032   93%   /
   devfs          205Ki  205Ki    0Bi   100%      710 
       0  100%   /dev
   map -hosts       0Bi    0Bi    0Bi   100%        0 
       0  100%   /net
   map auto_home    0Bi    0Bi    0Bi   100%        0  
       0  100%   /home
   map -fstab       0Bi    0Bi    0Bi   100%        0  
       0  100%   /Network/Servers
   

5. Then, insert the SD card and run the command again:

   $ df -h
   Filesystem      Size   Used  Avail Capacity  iused 
       ifree %iused  Mounted on
   /dev/disk1     232Gi  216Gi   16Gi    94% 56751576 
       4163030   93%   /
   devfs          211Ki  211Ki    0Bi   100%      730 
       0  100%   /dev
   map -hosts       0Bi    0Bi    0Bi   100%        0  
       0  100%   /net
   map auto_home    0Bi    0Bi    0Bi   100%        0 
       0  100%   /home
   map -fstab       0Bi    0Bi    0Bi   100%        0 
       0  100%   /Network/Servers
   
   /dev/disk2s6    63Mi   20Mi   43Mi    32%      512 
         0  100%   /Volumes/boot
   
   
   /dev/disk2s1   1.1Gi  1.0Gi   92Mi    92%        0 
         0  100%   /Volumes/RECOVERY
   
   

6. As you can see, /dev/disk2s6 and /dev/disk2s1 were added. This creates two partitions on disk2 - most SD cards will only have one, but however many there are mounted, you need to unmount them with diskutil:

   $ sudo diskutil unmount /dev/disk2s1
   Password:
   Volume RECOVERY on disk2s1 unmounted
   $ sudo diskutil unmount /dev/disk2s6
   Volume boot on disk2s6 unmounted
   

   Note

   Very important: Running dd on the wrong device will be disastrous - use with extreme caution!

7. There is a critical difference now from typical Linux drives and dd use. Let's say you had the aforementioned configuration and see that the SD card disk is disk2. For the dd command, you will change this to rdisk2:

   $ sudo dd bs=1m if=./2016-05-27-raspbian-jessie.img 
       of=/dev/rdisk2
   
   3833+0 records in
   3833+0 records out
   4019191808 bytes transferred in 377.097088 secs (10658241 bytes/sec)
   

   Note

   The dd command can take a while to run, and doesn't provide any output while it is, so you can get that feeling it might be stuck. Be patient, depending on the speed of your SD Card it could take several minutes to copy. Newer versions of dd (on Ubuntu 16.04 and newer) include the status=progress flag, which will indicate copying progress.

8. Finally, eject the disk, and you are ready to go!

   $ sudo diskutil eject /dev/rdisk2
   Disk /dev/rdisk2 ejected