Making a USB boootable from an ISO file

• Prepare a bootable USB by using RMPrep with grub4dos.
• Download an ISO file, e.g. Panda Safe CD ISO, "SafeCD.iso" 
• Mount that iso so we can view and access all files in that iso.
• Notice the dir structure in the iso. It should have a file call "isolinux.cfg". Look inside "isolinux.cfg" with text editor, It should mention a file that show up a menu upon starting up the iso. In this example, the file is called "menu.cfg".
• Look inside "menu.cfg" with text editor. It should show the detail of the menu. Here is:

LABEL live
    MENU LABEL Start SafeDisk
    kernel /live/vmlinuz1
    append initrd=/live/initrd1.img boot=live union=aufs



Here we have to adjust this accordingly to our menu.lst. This can be shown as


title Panda Safe CD
find --set-root /live/initrd1.img
kernel /live/vmlinuz1 boot=live union=aufs
initrd /live/initrd1.img

Notice all necessary files are in one directory. Here is directory called "live". Copy the whole "live" directory to our USB. Then put a new created menu.lst into the root of our USB.