Boot arguments for network boot in OF

If you are booting a power machine from CD you can just enter the boot arguments, for example:

 
 boot: linux vnc vncpassword=XXXXXX

The situation is different using network boot. There is no way to specify the boot arguments in the dhcpd.conf, Open Firmware only gets the boot file name and ignores everything else. To overcome this problem SUSE added the mkzimage_cmdline tool which can be used to hardcode boot arguments in the compressed network boot kernel.
For all other distributions you need to go to the Open Firmware prompt and supply arguments there.

Useful Information Modern yaboot now successfully netboots on IBM POWER. Which avoids having to specify arguments in OF or embed into the boot kernel. This allows selection of multiple targets.

• You will get OpenFirmware prompt if you press '''8''' at the start.

• Once there you need to issue '''ls''' command and determine the OpenFirmware path to the network device:

  0 > ls 
  000000c83378: /ibm,serial
  000000c84100: /chosen
  ...
  000000d191b8: /vdevice
  000000d1bc48:   /vty@30000000
  000000d1cb20:   /l-lan@30000002
  ...
  

• In our case the path to the first network card is ''/vdevice/l-lan@30000002''
  So now we can set an alias to this device:

  0> devalias net /vdevice/l-lan@30000002 
  

• And issue a network boot command followed by arguments we would like to provide:

  0> boot net vnc vncpassword=abc123
  

• Additional boot options for Red Hat Linux can be found here:
  http://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/ppc-multi-install-guide/ap-bootopts.html

If you are using bootp-server you may want to make a directed not broadcasted boot:

0> boot net:SERVERIP,,CLIENTIP,GW-IP ks=nfs:<server>:/<path>

See http://penguinppc.org/~hollis/linux/rs6k-netboot.shtml Netbooting IBM pSeries & RS/6000 by Hollis Blanchard