[syslinux] ISOLINUX 1.67 failure with no HDD; OK with HDD

[buckh at pobox.com]

Award BIOS 6.00PG, CD-ROM configured as first boot device
CD-ROM on IDE-1, master
variable: hard disk drive on IDE-0, master
no other IDE devs, no SCSI

if i boot with the HDD installed, ISOLINUX boots the CD OK with DL=9F.
if i remove the HDD, ISOLINUX fails to load the spec packet and can't
``wing it'' with DL=9F. (no maybe_msg's appear, either)

otherwise, this (and the venerable SYSLINUX) is (are) great stuff.
thanks, H. Peter. A.