Merge pull request raspberrypi#239 from LukeLR/master

XECDesign · XECDesign · commit d5701f7a978a · 2015-07-22T17:29:11.000+01:00
Improved description of image installation for mac
diff --git a/installation/installing-images/mac.md b/installation/installing-images/mac.md
@@ -11,34 +11,53 @@ On Mac OS you have the choice of the command line `dd` tool or using the graphic
 - From the terminal run:
 
     ```
-    sudo dd bs=1m if=path_of_your_image.img of=/dev/diskn
+    sudo dd bs=1m if=path_of_your_image.img of=/dev/rdiskn
     ```
 
     Remember to replace `n` with the number that you noted before!
 
+   - If this command fails, try using `disk` instead of `rdisk`:
+    
+       ```
+       sudo dd bs=1m if=path_of_your_image.img of=/dev/diskn
+       ```
+
 ## Command line
 
 - If you are comfortable with the command line, you can image a card without any additional software. Run:
 
     `diskutil list`
 
-- Identify the disk (not partition) of your SD card e.g. `disk4` (not `disk4s1`):
+- Identify the disk (not partition) of your SD card e.g. `disk4` (not `disk4s1`).
+- Unmount your SD card by using the disk identifier to prepare copying data to it:
 
-    `diskutil unmountDisk /dev/<disk# from diskutil>`
+    `diskutil unmountDisk /dev/disk<disk# from diskutil>`
 
     e.g. `diskutil unmountDisk /dev/disk4`
+    
+- Copy the data to your SD card:
 
-    `sudo dd bs=1m if=image.img of=/dev/<disk# from diskutil>`
+    `sudo dd bs=1m if=image.img of=/dev/rdisk<disk# from diskutil>`
 
-    e.g. `sudo dd bs=1m if=2015-05-05-raspbian-wheezy.img of=/dev/disk4`
+    e.g. `sudo dd bs=1m if=2015-05-05-raspbian-wheezy.img of=/dev/rdisk4`
 
-    This may result in an ``dd: invalid number '1m'`` error if you have GNU
+    - This may result in an ``dd: invalid number '1m'`` error if you have GNU
     coreutils installed. In that case you need to use ``1M``:
 
-    `sudo dd bs=1M if=image.img of=/dev/<disk# from diskutil>`
+       `sudo dd bs=1M if=image.img of=/dev/rdisk<disk# from diskutil>`
 
     This will take a few minutes, depending on the image file size.
     You can check the progress by sending a `SIGINFO` signal pressing <kbd>Ctrl</kbd>+<kbd>T</kbd>.
+    
+    - If this command still fails, try using `disk` instead of `rdisk`:
+    
+       ```
+       e.g. `sudo dd bs=1m if=2015-05-05-raspbian-wheezy.img of=/dev/disk4`
+       ```
+       or
+       ```
+       e.g. `sudo dd bs=1M if=2015-05-05-raspbian-wheezy.img of=/dev/disk4`
+       ```
 
 ## Alternative method
 
