Copying a Compact Flash card with OpenBSD
Instructions on how to make a backup copy of your OpenBSD CF installation using a USB CF card reader
This command works if you have a USB CF card reader you can hook up to your firewall box:
dd if=/dev/rwd0c of=/dev/rsd1c bs=1024k
rwd0c is the "C" partition of the OpenBSD install (which contains the other partitions). rsd1c (which may appear as rsd0c, etc) is the CF card in the USB card reader.
if = infile
of = outfile
bs = block size
Note: You don't need to mount the file system on the blank card.