Convert DMG Images To ISO Images
If you’re using OS X, you can burn a .dmg image to a CD/DVD via the Disk Utility. But what if you don’t have a CD/DVD burner on your Mac? Well, you can use the following command to convert your .dmg into an .iso.
hdiutil convert image.dmg -format UDTO -o new_image.iso
Your output file will have a .cdr extension, but you can just remove this. Now you can use a non-OS X machine to burn your CD/DVD.
Note: If an install image is broken up into multiple .dmg files (e.g., Install.dmg, Install.002.dmgpart, Install.003.dmgpart), this command will still work if the .dmgpart files are in the same folder as the main .dmg.