OpenBSD 5.7 on BeagleBone Black
-------------------------------

Last edited: $Date: 2015/06/28 10:34:59 $


## BeagleBone Black

The BeagleBone Black (http://beagleboard.org/BLACK) is an Arm-7
development board with a AM335x 1GHz ARM Cortex-A8processor, 512 Mb
DDR3 RAM, ethernet, microD slot, 4GB 8-bit eMMC on-board flash
storage and a lof other nice goodies. This board is capable of
running OpenBSD :)

In order to install OpenBSD on this board, you will need to access
the serial console. This is a 3.3 Volt RS232 serial console, and
connecting this with a 12 or even 5 Volt serial port will be fatal
for the board. You need an USB F-cable to connect the BeagleBone
Black serial port to your laptop or computer.

## Connecting the Serial Port

Locate the pins of the serial board on the BeagleBone Black. The
white dot is next to pin 1.

Use the following pins:

  * pin 1: Ground
  * pin 4: Receive
  * pin 5: Transmit

On this photo: http://box.matto.nl/ftx/bbb-serial.jpg you
can see the USB F-cable connected to the serial console.

I connected the other end (with the USB-connector) with my Debian
Linux laptop and started minicom. In minicom, choose for

  * Baud 115,200
  * Bits 8
  * Parity N
  * Stop Bits 1
  * Handshake None

Boot the board and check that you see the startup-messages.

Bring the board down.

## OpenBSD Installation image

For the BeagleBone Black you need the miniroot-am335x-57.fs
installfile from one of the OpenBSD ftp-mirrors.

You can copy this file with dd to a micro SD-card. I did this on a
Debian Linux laptop with:
    
    
    dd if=miniroot-am335x-57.fs of=/dev/mmcblk0 bs=16k
    

Funny thing is that you can use the same micro SD-card to install
OpenBSD on :)

So you dd the install image to a micro SD-card, start the installer
from there and install OpenBSD on the same card...

## Get the sets

This step is optional, just to make things easier.

I downloaded the setfiles from one of the OpenBSD ftp-mirrors:

  * base57.tgz
  * bsd.OMAP
  * bsd.OMAP.umg
  * bsd.rd.IMX
  * bsd.rd.OMAP
  * bsd.rd.OMAP.umg
  * comp57.tgz
  * game57.tgz
  * index.txt
  * man57.tgz
  * SHA256
  * SHA256.sig

I put these files on a local webserver, so during the install the
installation program can fetch these files from the local network.

I didn't bother to download any x-sets, this board will be running
headless.

## Start the installer

Now the hard work is done. Put the micro SD-card in the slot on the
board. Locate the small switch on to top-side of the board, close to
the micro SD-card slot (on the bottom-side). Keep this switch
pressed while putting power on the board. The board will now attempt
to install from the external micro SD-card and not from the internal
eMMC-flash storage.

The OpenBSD installer will start. Just follow the installation
procedure, I choose the defaults for the partitioning of the SD-card
(it is sd-card 0). After the installation is done reboot.

## Reboot into the installed system

After the reboot, login again via the serial cable and have a look
around your fresh OpenBSD system.

## Protect the micro SD card by mounting it readonly

To protect the life of the SD-card, we are going to make it
readonly.

Make sure your network configuration is right, ssh is hardened and
your ~/.ssh/authorized_keys has the right contents.

Make a directory /proto and copy /var and /home to it.
    
    
    mkdir /proto
    cp -rp /var /proto
    cp -rp /home /proto
    

Now, create a template for /dev

    
    
    mkdir /proto/dev
    cd /proto/dev
    cp /dev/MAKEDEV .
    ./MAKEDEV all
    

Now edit /etc/fstab, comment the entries for /dev, /var and /home out
and make the other entries readonly with noatime option:

    
    
    4a6b4c0ba6c86953.b none swap sw
    4a6b4c0ba6c86953.a / ffs ro,noatime 1 1
    4a6b4c0ba6c86953.f /usr ffs ro,noatime,nodev 1 2
    4a6b4c0ba6c86953.g /usr/X11R6 ffs ro,noatime,nodev 1 2
    4a6b4c0ba6c86953.h /usr/local ffs ro,noatime,nodev 1 2
    4a6b4c0ba6c86953.k /usr/obj ffs ro,noatime,nodev,nosuid 1 2
    4a6b4c0ba6c86953.j /usr/src ffs ro,noatime,nodev,nosuid 1 2
    # 4a6b4c0ba6c86953.d /tmp ffs rw,noatime,nodev,nosuid 1 2
    # 4a6b4c0ba6c86953.e /var ffs rw,noatime,nodev,nosuid 1 2
    # 4a6b4c0ba6c86953.l /home ffs rw,noatime,nodev,nosuid 1 2
    swap /dev mfs rw,nosuid,noexec,-P=/proto/dev,-i=128,-s=4096 0 0
    swap /var mfs rw,nosuid,noexec,-P=/proto/var,-s=8192 0 0
    swap /home mfs rw,nosuid,noexec,-P=/proto/home,-s=8192 0 0
    

Above, 4a6b4c0ba6c86953 is the uuid of the micro SD-card.

Each of the last three lines will make a memory file system (MFS) and
populate that with the corresponding subdirectory from the /proto
diretory.

Reboot and check everything works fine.

## Remounting read/write

In case you want to make some changes. install additional stuff, etc.
you can remount a partition by:

    
    
    mount -uw /
    

In this case / gets remounted read-write.

## Resources

The following pages where helpfull during the installation of OpenBSD
5.7 on the BeagleBone Black:

  * OpenBSD on BeagleBone Black Everything I wish I knew before
    installing the newly renamed armv7 port on a BeagleBone Black by
    Ted Unangst: http://www.tedunangst.com/flak/post/OpenBSD-on-BeagleBone-Black
  * Running OpenBSD off a USB Stick by Volker Roth: 
    http://www.volkerroth.com/tecn-obsd-diskless.html
  * OpenBSD on Soekris by John Hart: 
    http://blog.spoofed.org/2007/12/openbsd-on-soekris-cheaters-guide.html


$Id: openbsdbeagleblack.txt,v 1.2 2015/06/28 10:34:59 matto Exp $