If you try to use unetbootin to copy Hiren's bootcd on a usb flash drive and you boot using the flash disk, you'll notice that some options are missing, especially the "mini windows xp" boot option.
To overcome this problem you have to copy the file "HBCD/isolinux.cfg" to the main folder and replace the file "syslinux.cfg"
Then everything will work as expected.
Bug report: https://bugs.launchpad.net/unetbootin/+bug/971403
