Suppose you have an iso image that contains a bios bootable partition.
You can write this image to a usb disk
In linux you could do this for example with
dd if=pmagic_2013_02_28.iso of/dev/sdc1
Your USB disk is now bootable on computers with bios.
However on my UEFI system, the usb disk does not boot. How can you make it EFI bootable?
Best Answer
Some magic of El Torito is required when creating the iso image. See this.