This is beyond my experience level, but I'd try wiping the disk and starting over. Try booting your OS X CD, re-running Disk Utility, delete the partitions, re-initialize the disk, re-create the partitions.
At that point, you could boot the OpenBSD CD and see if fdisk sees the partition map. But remember to install Mac OS first because you won't be able to copy the bootloader to the HFS+ partition without it. On Thu, 2017-11-02 at 05:00 +0100, SFM wrote: > I tried that too (marking the partition as unused through disk utility in > order to install OpenBSD later), same result !
