Installing OpenBSD from a USB flash drive

[hanzer]

I wanted to upgrade a 5.5-i386 machine to 5.6-i386 with a fresh installation and a new disk partition layout. There were no blank CD's in the house but there was an old USB thumb drive that might do the trick. The FAQ has a section - Creating a bootable install flash drive from Unix - but I suspect that installation method would require network access. Unfortunately, the target machine's wpi(4) network interface requires an fw_update(1) with non-free firmware before it is usable.

This method creates a bootable USB installation device (yeah, I said "installation device" (hey, it's been a long day)) from the contents of the install56.iso CD image.

First, inspect the USB device:

From $ dmesg
sd1: 247MB, 512 bytes/sector, 506880 sectors

This one is ancient and barely has enough capacity but it will work.

Then as root: (in the following, be sure to replace values in red with values from your USB drive)

vnconfig vnd0 install56.iso
mount /dev/vnd0a /mnt
tar xzf /mnt/5.6/i386/base56.tgz -C /tmp/
dd if=/dev/zero of=disk.img bs=512 count=506880
vnconfig vnd1 disk.img
fdisk -y -f /tmp/usr/mdec/mbr -i vnd1
echo "a\n\n\n\n\nw\nq\n" | disklabel -E vnd1 
newfs /dev/rvnd1a
mkdir /mnt2
mount /dev/vnd1a /mnt2
cp -r /mnt/* /mnt2/
installboot -r /mnt2 vnd1 /tmp/usr/mdec/biosboot /tmp/usr/mdec/boot
dd bs=512 count=506880 if=disk.img of=/dev/rsd1c
umount /mnt
umount /mnt2
vnconfig -u vnd1
vnconfig -u vnd0
rmdir /mnt2
rm disk.img

And that seems to work.

[shep]

I may be missing something here but why not use

install56.fs

with

# # dd if=/location/install56.fs of=/dev/rsd1c bs=1m? This assumes the drive is recognized as sd1.

See the FAQ for more details.

After the install, reformat the usb drive

# newfs -t msdos sd1c

Download the firmware (assuming you have access to a second computer) and copy it to the thumb drive. Load the firmware on the new OpenBSD 5.6 install from the thumb drive, configure wireless and go from there.

What would be kinda of neat would be to mount the image loopback and insert the needed firmware. The Debian developers also share the OpenBSD view on distributing proprietary firmware and have an install option where the firmware can be accessed from removable media (floppy, usb thrumb drives and CD's). I wonder if it is possible to escape to a command prompt during the OpenBSD install and mount a usb drive and load the firmware for a network install?

[jggimi]

Originally Posted by shep

See the handbook ...

we call it a FAQ.

I wonder if it is possible to escape to a command prompt during the OpenBSD install and mount a usb drive and load the firmware for a network install?

Yes, but the RAMDISK kernel has very limited freespace on that ramdisk. A post-install fw_update(1) is much easier.

[ibara]

Originally Posted by shep

I wonder if it is possible to escape to a command prompt during the OpenBSD install and mount a usb drive and load the firmware for a network install?

Yes. Lots of people do this. You can drop to a shell by typing ! anywhere in the installer.

[hanzer]

Originally Posted by shep

I may be missing something here but why not use install56.fs

Oh geez, I'm retarded. When I saw that in the FAQ, for some bizarre reason I assumed install56.fs was a floppy image meant to be used in some kind of network install. If it's a full install image for a USB device, the method I posted is kind of pointless.

I think I will spend the next Friday the 13th in bed.

[shep]

I assumed install56.fs was a floppy image

I think it is a reasonable mistake. Most USB install images are suffixed with *.img The full USB install images were recently made available in OpenBSD and for some reason the project choose to use the same *.fs suffix as the floppy images.

[bsd-keith]

Don't sweat it hanzer, that's a neat bit of code for someone new to OBSD.

[ibara]

Originally Posted by hanzer

I assumed install56.fs was a floppy image meant to be used in some kind of network install.

That would be floppyXX.fs
Also, check file sizes:
floppy57.fs 13-Feb-2015 14:25 1.4M
install57.fs 13-Feb-2015 14:25 280M

There's also a minirootXX.fs that is a USB installer where you bring your own sets (such as http install).