There are several options that you may need to configure when adding a boot image to your project.
Local Path
In this field you should specify the local path of the selected boot image. The path is relative to the root folder of the disc. For example: /boot/ will create a folder called boot in the root that contains the file that you have selected.
Emulation Type
This option lets your specify the type of emulation that should be used on the "El Torino" boot disc. If the emulation type is set to Floppy, the boot image must be exactly the size of a 1200, 1440 or 2880 KiB floppy. If the emulation type is set to Harddisk, the boot image must begin with a master boot record that contains a single partition. Using no emulation will cause the system to load and execute the image without performing any disc emulation.
Advanced Options
The Don't make image bootable option allows you to prevent the disc from beeing marked as bootable. The system will provide an emulated drive for the image, but will boot off a standard boot device.
Enabling the Write boot-info-table to the image option will cause the boot image to be patched at offset 8 with a 54-byte table containing information about the disc layout. If this option is enabled the local boot image that you have specified will be patched, so make sure that you have a backup of this file if it can't be easily regenerated.
The Boot load segment option allows you to specify the load segment address (in hexadecimal) for no-emulation "El Torito" discs.
The Boot load size option allows you to specify the number (in hexadecimal) of virtual (512-byte) sectors to load in no-emulation mode. It's usually recommended to load the entire boot file. Some BIOSes may have problems if this size is not a multiple of 4.