iso_image_give_up_mips_boot().
The preliminary ban has been lifted to combine El Torito and MIPS Big Endian
boot facilities.
The current state of boot record documentation has been added to bzr.
an MBR with a first partiton table entry that bears non-zero start address.
A second set of volume descriptors and directory tree+tables gets created
which can be used to mount the image at the partition start.
Not yet implemented for second set: ISO 9660:1999, MD5 checksums.