El torito (boot) patch


IsoBuster - El torito (boot) patch

Size of the boot images

Strictly based on the boot catalog

Determines the size of the boot images purely based on the information contained in the El Torito structures on the disc

Use mkisofs patched image file length if present

Bootable CD/DVDs made with mkisofs can contain some extra information on the size of the boot image.  The size of the boot image as recorded in the El Torito (specification) structures may in fact be wrong for the generated boot image.  The real size is then recorded in the special mkisofs structure.  Mkisofs provides this functionality because some BIOS can only deal with certain boot image sizes (in no emulation mode).  So the size in the El Torito structures is purposely wrong then, but the real size is recorded in the special structure.  IsoBuster will display (an extract if requested) the correct size, based on the mkisfs structure, if this option is enabled.

Calculate based on MBR or BPB in case of a FAT volume

Uses FAT data to determine the boot image size

Calculate based on next boot image

Uses the area up to the next boot image

Hard coded (based on signature recognition)

Based on hard coded values, determined via reverse engineering


Check boot images for FAT content and list files if FAT is present

Sometimes, not always, the boot file (*.img) of a bootable CD or DVD contains a FAT file-system.  For instance the boot image file of the Windows 98 installation disc is a 1.44 MB floppy image with a FAT12 file-system inside.  If this option is enabled, IsoBuster checks the boot image file while mounting and if the boot image file contains FAT, IsoBuster then adds a FAT file-system to the disc layout and shows all files and folders inside the FAT file-system, in other words IsoBuster then shows the files and folders contained in the boot image file.


Scan options (normal mounting of discs)
Text conversions
Mac properties and extraction methods
Write software specific options