Under Linux, I can simply do a: dd if=ubuntu-14.04.1-desktop-amd64.iso of=/dev/sdband boot up the /dev/sdb which is a device for a flash drive. It finishes in 263 seconds. But: If I boot up an OpenBSD 5.6 and do the same (for the same flash drive, zeroed it between the two tests): dd if=ubuntu-14.04.1-desktop-amd64.iso of=/dev/rsd1iIt takes about half an hour to finish (using securelevel 1), but when I boot up the flash drive from it the BIOS only says: no active partition foundQuestion: what am I missing? 
Write an image to a flash drive under OpenBSD
openbsd;block device
You're using the wrong partition letter. Try with this:dd if=yourisofile.iso of=/dev/rsd1cReplace 1 by the correct number of your device (search this info in the dmesg). Read the Wikipedia article about BSD disklabels to learn why with the c works and with i doesn't.