grub: loopback

 
 16.3.44 loopback
 ----------------
 
  -- Command: loopback [-d] device file
      Make the device named DEVICE correspond to the contents of the
      filesystem image in FILE.  For example:
 
           loopback loop0 /path/to/image
           ls (loop0)/
 
      With the '-d' option, delete a device previously created using this
      command.