Hi,
I never tried to make a Mac bootable CD with mkisofs, I did make, but
using Toast.
Anyway you seem to ignore some basic Macintosh concepts, so it may help
to fix those.
A Macintosh bootable CD is in no way a ISO standard. In fact it is just
the bit per bit image of a Macintosh hard disk.
Macintosh hard disks can be formatted either HFS or HFS+. The same for
a Mac bootable CD, although I would suggest to stick to HFS.
(More: you talk about System 7.5.3: that version of the System DOES NOT
recognize HFS+ = one definitive reason to use HFS)
Hard disks usually have a partition map at the beginning. A Mac
bootable CD MUST begin with a partition map otherwise the Mac may still
be able to read, but would never accept as a bootable system disk.
Mkisofs in the newer versions has the ability to make hybrid images,
that is, CDs with both a ISO 9660 directory and a Macintosh HFS
directory.
That is not enough to make a bootable CD, as I just explained it also
needs a Macintosh partition map if you want a Mac to ever consider
booting from there.
Toast has the ability to make such a map, Apple's Disk Copy has not,
don't know mkisofs.
If mkisofs can not produce the partition map then you are out of luck.
(in fact there is a way, but its hard and dirty and I will explain only
if you find no better way)
Apart from the format, a Mac bootable CD must contain a System folder
with system stuff inside, probably you already realized this.
More and basic: the System folder must be "blessed" (especially
marked): did you blessed it ?
Again you have to investigate whether mkisofs supports such an option.
Finally one very stupid point, which Mac do you want to boot with
System 7.5.3 ?
(It is not supported by recent Macintoshes)
Hope this be of help.
I am amused about one point: if Apple allows downloading for free the
files which make up System 7.5.3, why not the full CD image ?
Danilo
