I downloaded the debian amd 64-bit iso file (apx 650 mb) on a macbook w/retina (i.e. no cd drive) running OS X. I'm trying to dual boot and have already gotten rEFInd working. Set up partition for Debian with MS-DOS(FAT) format and blessed it. Now I'm trying to burn the .iso onto a usb to use for installation on the same computer. I'm using Terminal to convert .iso to .img with: hdiutil convert -format UDRW -o ./debian-7.8.0-amd64-CD-1\ \(1\).img ./debian-7.8.0-amd64-CD-1\ \(1\).iso but it keeps outputting hdiutil: convert failed - No such file or directory Not sure what I'm doing wrong.

EDIT: I've succeeded in converting the .iso to .img and I'm attempting to unmount the disk partition I've made for debian via diskutil unmountDisk /dev/disk0s5 but I keep getting Unmount of disk0 failed: at least one volume could not be unmounted. I've verified this is the right disk using diskutil list. Any ideas what is wrong?

  • Does ls show the debian iso file in your present working directory? Jan 14, 2015 at 21:26
  • No. It turns out I was in the wrong directory. I changed directories, and this caused the convert to run but there was a syntax error. After renaming the file to so the input was ./debian-7.8.0-amd64-CD-1 it ran properly.
    – hohos6
    Jan 15, 2015 at 22:23

2 Answers 2


you can burn your iso file directly to usb by the command dd

sudo dd if=<Your iso file location> of=/dev/<Your usb drive>(usually=/dev/sdb)

note:use sudo fdisk -l to see what is your usb device name

Example : i connect my usb thumb drive ,then i type sudo fdisk -l to show my device name , its (/dev/sdb) so i will type : sudo dd if=./debian-7.8.0-amd64-CD-1 of=/dev/sdb

enter image description here

  • I usually run dmesg to see what device is added most recently (i.e. near the end of the output).
    – wurtel
    Jan 15, 2015 at 8:17
  • 1
    Thanks for the tip, both of you. I was planning to copy the .img directly to the partition using $ sudo dd if=debian7.8.0-amd64-CD-1.img of=/dev/disk0s5 bs=1minstead of burning to usb. Would that work?
    – hohos6
    Jan 15, 2015 at 22:30

The Debian installation guide now recommends the simpler cp command to write an ISO image to a USB drive:

# cp debian.iso /dev/sdX
# sync

This requires root or sudo access and sdX is the relevant USB device (eg. /dev/sdb), not the partition (eg /dev/sdb1).

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