The ISO-9660 file generated by mkisofs is broken. SOme files can't be
readed. It seems that this depend on their place in the image. Same problem
with loopback and burned CD. Content of the file does'n matter.

Reproducible example of making crapped image:

mkdir /tmp/test
dd if=/dev/zero of=/tmp/test/file ibs=10240 count=1
mkisofs -r -o /tmp/isofile /tmp/test
mount -o loop /tmp/isofile /mnt/cdrom
cat /mnt/cdrom/file
[input output error appear here]