gzip generates 'unexpected end of file'

[Steven Rogers <srogers gunstar com>]

In the process of creating new distos using RH9 boot CD's.
 
I was creating distros using 7.3 and it's bootloader.  Heavily hacked up 
and was using the older dosutils/autoboot/cdboot.img file before.

At this point, I'm trying to mount the initrd.img file from the 
bootdisk.img so that I can drop a new ks.cfg file into it, but am bombing 
out trying to extract it.

rm -f initrd.floppy initrd.floppy.gz
mount -o loop cdrom/images/bootdisk.img mnt/floppy
gzip -dc mnt/floppy/initrd.img > initrd.floppy

gzip: mnt/floppy/initrd.img: unexpected end of file

Any help/ideas?

Second question - What is cdrom/images/boot.iso for?

TIA,

Steven