Table of Contents

Ubuntu - ISO - Create ISO from a Bootable USB Drive - Using mkisofs

mkisofs creates ISO 9660 file system images, typically for generating CD and DVD images.

Convert to ISO File

First, let’s install mkisofs: 

sudo apt install mkisofs

Create a mount point: 

mkdir /mnt/usb_drive

Mount the USB drive

sudo mount /dev/sdb1 /mnt/usb_drive

Create the ISO image from the mounted directory

sudo mkisofs -o myisofile.iso -R -J -input-charset utf-8 /mnt/usb_drive/

returns: 

Total translation table size: 0
Total rockridge attributes bytes: 3852
Total directory bytes: 123456
Path table size(bytes): 141
Max brk space used 26000
1312794 extents written (999 MB)

NOTE:

  • -o: specifies the name of the output ISO image file.
  • -R: generates the Rock Ridge extension for UNIX file attributes.
  • -J: generates the Joliet extension for Windows file systems.
  • -input-charset utf-8 the character encoding to be used when creating the ISO image.

Verify the ISO file

isoinfo -d -i myisofile.iso

returns: 

CD-ROM is in ISO 9660 format
System id: LINUX
Volume id: CDROM
... 
Volume set size is: 1
Volume set sequence number is: 1
Logical block size is: 2048
Volume size is: 123456
Joliet with UCS level 3 found
Rock Ridge signatures version 1 found

NOTE: The resulting output confirms that the myisofile.iso file is in the ISO 9660 format.