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Install your own Open Firmware tags System
This seems to be something prone with the possibilities of major damage to your system — I'm merely pointing this avenue of research out as raised by another webpage, with the preface that you shouldn't even approach doing this until you are quite confident in the knowledge of what you are doing!

This webpage speaks of how the command nvram, located in the /usr/sbin directory, can be used to "list and set open firmware settings," including "specify[ing] your own settings. For example, you could create a variable called asset_tag and keep the asset inventory tag of that particular computer in the firmware."

This particular tip was thought of by the webpage's author as a hint for people running computer labs, but it could be used by other Mac OS X users, I'm sure.

I'd really, really pause and make sure you know what you're doing before goofing around with your computer's firmware, though ... talk about playing with dynamite!

[Editor's note: I'll echo the sentiment -- this is published here mainly in the interest of completeness. Do NOT mess around with Open Firmware unless you really really know what you're doing!]
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Install your own Open Firmware tags | 2 comments | Create New Account
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boot-args
Authored by: mervTormel on Jan 29, '02 11:44:53PM

when i first started running OSX, this is where i set the parameter to always boot into single-user mode:

% sudo nvram boot-args="-s"

i was stress testing the system by crashing it, and observing fsck results.

N.B.: booting into OS9, i believe, whacks this particular value back to nil



[ Reply to This | # ]
OF tinkering is safe.
Authored by: Anonymous on Jan 31, '02 08:01:17PM

Adding new variables to OpenFirmware has little risk of damaging your computer. This is a feature, and not a hack of OpenFirmware. The real risk comes when cluebies start modifying existing values.

I use custom OpenFirmware values for my contact information, and asset tag #'s. Hardly anyone, but perhaps staunch geeks would know to check here, and OF variables survive reinstalls/etc.

'man nvram' for more information...

also, check out here:

http://bananajr6000.apple.com/OF/technotes.html

Now I just need to port/code the two utilities you need to display custom bootup logos via OpenFirmware. Solaris has them: iconedit, and uhhh, I forget the other one.

To set arbitrary variables:
- Go into the OpenFirmware prompt (if you don't now how to do this, stop here)
- Type nvram -p, and make sure the variable names you want to create don't already exist.
- If they don't already exist, you can create variables using the following format:
<pre>
% sudo nvram variablename="text you want here"
</pre>

For example, I have the following variables set in my OF:
<pre>
% sudo nvram my-owner="John Doe"
% sudo nvram my-phone="555-555-1212"
% sudo nvram my-assetnum="BC45312"
</pre>

This is cool, because you can set organizational information in a hard-to-destroy way that survives hard disk crashes, etc. It also allows you to pull organizational information via scripts or other remote tools, using the nvram command as so:

nvram variablename
<pre>
% nvram my-owner
my-owner John Doe
</pre>



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