This tip assumes the ENTIRE disk will be used for OpenBSD.

First initialize the MBR, and overwrite using the default template:

Note: Substitue sd1 for your disk

Next use disklabel to modify the current partition layout:

Note: p m will display the current partitions on the disk

Delete all partitions except c:

Note: The “d” deletes the specified partition. “d a” deleted partiton “a”

Create the new OpenBSD partition on the disk:

Note: Change the 34700m to the full size of the disk you have. The disk in this example was 34.7Gb in size.

Now build a new file system on the disk using the following command:

Finally, make a directory where you would like to mount the disk.

Mount the disk.