dnl	$OpenBSD: prep,v 1.1 2008/05/13 20:47:32 kettenis Exp $
To be able to boot the OpenBSD/MACHINE installation program, you will
need to learn a bit about Das U-Boot, the low-level process that controls
the microprocessor after hardware initialization.

Talking to the Thecus

The Thecus N2100 needs a serial cable. On the back of the disk drive
circuit board, there is either a 10-pin header (with one pin removed),
or 9 holes for you to solder in your own header.  The ribbon cable
that connects from there to your serial cable or the serial port on
your computer is of the same type as used on older i386 PCs, but
be aware that there are two different types of 10-pin IDC to DB-9M
ribbon cable in use, which look identical (the differences are hidden
inside the DB-9 connector). The cable you need is wired using the
"AT-Everex" or "Asus" pinout, as described here:

    http://www.pccables.com/07120.htm

and *not* the more straightforward to solder "crossed" type:

    http://www.pccables.com/07121.htm.

If you wish to check a cable, or make your own, the pinouts are:

    DB9           IDC10
    ===           =====
    1 2 3 4 5     1 3 5 7 9
     6 7 8 9      2 4 6 8 10

Wire pin 1 to 1, 2 to 2 etc, with 10 not connected.


Booting Thecus N2100

When you have connected your computer, a command like "tip -115200 tty00"
(assuming you're using the first serial port on your machine) should 
connect you to the Thecus console. Now apply power to the Thecus
and start it.

After some device probe information, you should see this prompt:

    Hit any key to stop autoboot:  1

You have exactly one second to press a key and enter interactive
U-Boot.  Fortunately it will typically accept a key typed during the
diagnostics that precede thus prompt.

The recommended way to boot OpenBSD on Thecus is to configure networking and
load bsd.rd from a tftp server or http server. First networking must be
configured using the setenv command.

    => setenv ipaddr 10.0.0.21
    => setenv serverip 10.0.0.7

Once you have done this, and have set up your TFTP server on
the gateway machine (10.0.0.7 in the above example), you can
boot manually.

    => tftpboot 200000 bsd.rd
    Speed: 1000, full duplex
    Using Freescale TSEC0 device
    TFTP from server 10.0.0.7; our IP address is 10.0.0.21
    Filename 'bsd.rd'.
    Load address: 0x200000
    Loading: ##########################################################
          #############################################################
          ...
          ######
    done
    Bytes transferred = 295148 (480ec hex)
    => go 200000

Copyright (c) 1982, 1986, 1989, 1991, 1993
     The Regents of the University of California.  All rights reserved.
Copyright (c) 1995-2008 OpenBSD. All rights reserved.  http://www.OpenBSD.org

OpenBSD 4.3 (RAMDISK) #175: Tue Mar  4 21:54:34 MST 2008
    deraadt@socppc.openbsd.org:/usr/src/sys/arch/socppc/compile/RAMDISK
real mem = 67108864 (64MB)
avail mem = 63012864 (60MB)
...
Install(I), Upgrade(U) or Shell(S)?

If you then install to your hard disk, in future you can
load the OpenBSD/socppc boot loader

    => tftpboot 100000 boot
    => bootm

and just hit "return" to boot OpenBSD.


Automatic Booting

However, for easier booting, you may wish to modify the flash
memory so that the Thecus will boot automatically into OpenBSD
when it is powered up.

    => erase fe780000 fe800000
    
    .... done
    Erased 4 sectors
    => tftpboot 200000 boot
    Speed: 1000, full duplex
    Using Freescale TSEC0 device
    TFTP from server 10.0.0.7; our IP address is 10.0.0.21
    Filename 'boot'.
    Load address: 0x200000
    Loading: ##########################################################
    done
    Bytes transferred = 295148 (480ec hex)
    => cp 200000 fe780000 20000
    Copy to Flash... 
    512 KBdone
    => setenv bootcmd bootm FE780000
    => saveenv
    Saving Environment to Flash...
    Un-Protected 2 sectors
    Erasing Flash...
    .. done
    Erased 2 sectors
    Writing to Flash... 
    256 KBdone
    Protected 2 sectors
    => reset

This configuration can easily be set back to the default, as the
Linux system does not get erased from the flash memory. To set it
back, just change the boot script with fconfig back to what it was,
for example:

    => setenv bootcmd flashboot
    => savenv

The bootloader is command driven with timeout like many other OpenBSD
architectures.