I came across this problem this morning, while writing the newly downloaded moblin USB image file. The concept is straight forward, plugin a 1GB+ USB stick into a functioning Linux or Windows box, make sure the stick is not mounted and use dd to write the disk image to the stick. Under OSX however the instructions for unmounting are slightly different, so here are the quick steps:
- Download the desired .img file
- Open a Terminal (under Utilities)
Run diskutil list to get the current list of devices
- Insert your flash media
Run diskutil list again and determine the device node assigned to your flash media (e.g. /dev/disk2)
Run diskutil unmountDisk /dev/diskN (replace N with the disk number from the last command; in the previous example, N would be 2)
Execute sudo dd if=/path/to/downloaded.img of=/dev/diskN bs=1m (replace /path/to/downloaded.img with the path where the image file is located.
Run diskutil eject /dev/diskN and remove your flash media when the command completes
That should do it…..