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Chapter 1B. Manual Download and Verification of Debian on OS X.

IMPORTANT NOTE: This part of the guide is experimental. It may not work as expected and, in
the worst case scenario, may result in an unbootable system. Additionally, the method described 
in Chapter 2A may not work if you intend to use the drive on other machines. If you attempt to 
use this guide with an Apple computer, PLEASE BACK UP ALL OF YOUR IMPORTANT 
FILES BEFORE DOING ANYTHING ELSE TO AN EXTERNAL DRIVE IN CASE YOUR 
APPLE COMPUTER BECOMES UNUSABLE!

1. Open the Safari web browser in your dock bar and go to “gpgtools.org”.

Chapter 1B. Manual Download and Verification of Debian on OS X.
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2. When the page opens, scroll down until you see the “Download GPG Suite” link. Click on the 

“Download GPG Suite” link. Your download will start automatically and you will be taken to a 
donation page.
  

3. When the download completes, click on the “downloads” icon in your Safari web browser 

located in the upper right section of the browser and double click on the “GPG Suite” installer.

Chapter 1B. Manual Download and Verification of Debian on OS X.
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4. When the GPG Suite installer opens, double-click on the “Install” button..

Chapter 1B. Manual Download and Verification of Debian on OS X.
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5. On next screen, click “Continue.”

Chapter 1B. Manual Download and Verification of Debian on OS X.
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6. On next window, click the “Install” button.

7. Next, you will be prompted for your password. Type your password and click “install software.”

Chapter 1B. Manual Download and Verification of Debian on OS X.
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8. When install finishes, click the “Close” button.  You can then close the GPG Suite installer 

window.

Chapter 1B. Manual Download and Verification of Debian on OS X.
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9. You can close any GPG program windows and Safari if you wish.  Then, click on the 

“Launchpad” icon in your dock bar, type “terminal” and click on the “Terminal” icon that 
appears.

10. When the terminal window appears, you will next import the Debian CD signing key.  In the 

terminal, type “gpg --recv-keys DF9B9C49EAA9298432589D76DA87E80D6294BE9B”.

If the key import was successful, your output will look like the output pictured below.

Chapter 1B. Manual Download and Verification of Debian on OS X.
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11. Next, verify the fingerprint of the Debian CD signing key. Type “gpg --fingerprint 

DF9B9C49EAA9298432589D76DA87E80D6294BE9B”

Your output should mirror what is pictured below.  If it does not, start over from step 10.

12. Now, download the Debian Installer ISO image.

If you have a 32 bit processor, or 4 gigs of RAM or less, type  “curl -L -O 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/i386/iso-cd/debian-8.7.0-i386-
netinst.iso
” press enter. 

If you have a 64 bit processor, type “curl -L -O 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/amd64/iso-cd/debian-8.7.0-
amd64-netinst.iso
” and press “enter.”

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13. Next download the hash checksum file to verify that the Debian ISO image you downloaded 

hasn't been tampered with. 

If you have a 32 bit processor, or 4 gigs of RAM or less, type  “curl -L -O 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/i386/iso-cd/SHA512SUMS” press
enter. 

If you have a 64 bit processor, type  “curl -L -O 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/amd64/iso-cd/SHA512SUMS” 
press enter. 

14. Next, download the GPG signature file to verify that the Debian checksums haven't been 

tampered with.  

If you selected the 32 bit processor (i386) related checksums in the last step, type “curl -L -O 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/i386/iso-cd/SHA512SUMS.sign” 
and press “enter.”

If you selected the 64 bit processor (amd64) related checksums in the last step, type “curl -L -O
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/amd64/iso-
cd/SHA512SUMS.sign
” and press “enter.”

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15. Now, verify your downloads.  This will help ensure that you have a legitimate version of 

Debian that has not been tampered with.  In this step, you will verify the legitimacy of the 
checksum file. Type “gpg --verify SHA512SUMS.sign SHA512SUMS”.

The output from the command above should look like the screenshot below with a “good 
signature.” However, if the output states “bad signature,” your download or keyfiles have been 
corrupted or tampered with.  If you get a “bad” result, restart from step 12. 

NOTE: You can ignore the “warning” that the “key is not certified.” This is not relevant in the 
context.

16. Next, verify that the Debian ISO image is not corrupt and has not been tampered with. Type 

cat SHA512SUMS |egrep netinst |shasum -c -”.

Note: The symbol in the line to type above that looks like a vertical line is known as the “pipe” 
character. On an Apple keyboard, it is generally accessed by holding shift and pressing the “\” 
key that is often above your “enter” key. 

You should get a result saying the version of Debian you downloaded is “OK” like the screen 
shot below.  If it says otherwise, start again from step 12. 

NOTE: The next steps are for copying the image to a USB disk. If you intend to burn the 
Debian Installer ISO to a bootable CD, do so now and continue to Chapter 1D.

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17. Next, you need to convert the Debian ISO image to a format that can boot from your USB disk 

for a Mac.  Type “for f in debian-*-netinst.iso; do hdiutil convert -format UDRW -o 
debian.img $f; done
” and press “enter.”

18. Next, type “diskutil list” and press “enter.”  

This will show you the accessible disk drives on your system. It will look like the screen shot 
below.  Remember what it looks like.

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19. Next, insert your USB disk drive that you intend to use as the install disk and type “diskutil 

list” and press “enter” again. 

Your USB disk will appear as the disk you didn't see in the last step. It will likely have the 
device name of “/dev/disk2.” However, depending on the number of disks or disk partitions you
have for your system, it may be a different device name.  The easiest way to determine which 
device marks your USB disk is based on the total storage capacity of the disk. For the 
remaining steps in Chapter 1B, “/dev/disk2” will be used strictly for example purposes.  
You should replace “/dev/disk2” with whatever device name your USB drive is using.

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20. Now, unmount your usb disk. This is required in order for the next step to work. Type “diskutil 

unmountDisk /dev/disk2”and press enter.  Again, “/dev/disk2” is only used for an example 
purpose. Please substitute “/dev/disk2” with the device name of your USB disk if 
applicable.

21. Next, create your bootable disk. Typing “sudo dd if=debian.img.dmg of=/dev/disk2 bs=1m” 

and press enter. Again, “/dev/disk2” is only used for an example purpose. Please substitute 
“/dev/disk2” with the device name of your USB disk if applicable. BE WARNED THAT 
THIS WILL ERASE THE CONTENTS OF WHATEVER DISK YOU CHOOSE!
 Thus, it 
is imperative that you select the correct disk.

22. Finally, when the task of creating the bootable USB installation disk is completed, you will be 

returned to a command prompt. Type “diskutil eject /dev/disk2” and restart your computer.  
Continue from Chapter 1D.  Again, “/dev/disk2” is only used for an example purpose. Please 
substitute “/dev/disk2” for the device name of your USB disk if applicable.

After you are returned to your command prompt, restart your computer and 

continue from 

Chapter 1D

 

 .