When trying to get the autorun file to execute from USB at startup, the rc.S file does not seem to be able to mount /dev/sda1.

I found that when mounting /dev/sda all was fine.

doing an
# fdisk -l
reported all kinds of errors from each partition.

When we tried to reformat it from an XP box and reload it, it did not appear to fix the issue.

To repair this, we needed to run fdisk and redo the partitions from scratch.
Then perform the format from the XP box.

Then all was ok!