Under Linux, I can simply do a:

dd if=ubuntu-14.04.1-desktop-amd64.iso of=/dev/sdb

and 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/rsd1i

It 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 found

Question: what am I missing?

  • 2
    /dev/rsd1i - I don't know how OpenBSD names drives, but that 1i makes me think that's a partition of that disk, not the disk itself. – muru Jan 21 '15 at 15:02
  • @muru I believe you are correct. Why don't you post as an answer – Chris Mendez Jan 21 '15 at 15:15
  • @ChrisMendez I would, if I had any experience with OpenBSD at all, or if I could explain the speed difference. With neither, all I have is a guess. :( If you post one, I'd +1 it, though. – muru Jan 21 '15 at 15:17
  • 2
    You should pass a blocksize to use with dd in such cases, e.g. dd bs=512k ... for 512KB blocks, that should speed it up. – wurtel Jan 21 '15 at 15:28

You're using the wrong partition letter. Try with this:

dd if=yourisofile.iso of=/dev/rsd1c

Replace 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.

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