Reset NVRAM
By on March 23rd, 2005
(I last checked the links below on this day: Friday, 23 January, 2009.)
This is my most requested post topic. It is always appearing multiple times in my referral stats. So, without further delay, here is a consolidated informational on resetting your Macintosh NVRAM (aka “nonvolatile RAM”).
According to Apple Support documents, Article Number 2238, the proper method for resetting the NVRAM involves accessing Open Firmware.
First, Open Firmware and why the heck would you want to go monkeying around in there:
Open Firmware is normal behind the scenes stuff that most users will never access or need to, however, if you experience odd behaviour and Google for solutions, chances are you may see someone mention OF somewhere for something. According to Apple Support document number 93772, Open Firmware is the name given to a specific kind of firmware compliant with IEEE Standard 1275-1994. That doesn’t mean much to me either, but here’s what the rest of the definition states:
“Among Open Firmware’s many features, it provides a computer independent device interface – usually for PCI or AGP cards. This enables expansion card manufacturers to easily support several different computer designs without supplying different firmware for each one.
Generally you won’t interact with Open Firmware. An example of when you might need to is if you see this message on the screen: “To continue booting, type ‘mac-boot’ and press return.”"
Ok, but if I choose to reset my NVRAM, I need to access this mystical OF. When booting up your Mac, pressing and holding the Command-Option-O-F key combination during startup will send your Mac to the OF interface instead of your familiar routine.
According to Apple, the necessary steps to reset are as follows: (info found at Apple Support document 106482 all the way at the bottom and here Apple Support document number 2238)
1. Start up into Open Firmware by pressing and holding the Command-Option-O-F key combination during startup.
2. At the Open Firmware prompt, type: reset-nvram
3. Press Return.
4. When prompted for your password, enter it and press the Return key. It responds OK.
5. At the Open Firmware prompt, type: reset-all
6. Press Return.
Your computer will restart after you type in the bit on instruction number five.
Just a tip: I know this is one of the most accessed keywords in my blog, but if you don’t know why you’re trying to reset your NVRAM, don’t do it. It’s not a regular maintenance or troubleshooting thing to do. Do the Disk Utility from your Start-Up dvd or cd, repair your permissions, use a third-party troubleshooter/repair like Disk Warrior, trash .plists that you know can be deleted without harming your system or apps, call a friend, seek an Apple repair place or go see a Genius at the Apple Store… do as little spooky stuff to your Mac as you can. Be gentle. It’s a damn good computer but as with anything, the wrong tool for the wrong job can do more harm than good.
You can also find information on Open Firmware Password Protection and why to use it in certain circumstances here in Apple Support document number 106482, (same article as quoted above).
Hope this helps to point y’all in the right direction. Good luck and remember to troubleshoot in as many other ways as possible before getting kooky with firmware stuff, terminal, or other things that the average user wouldn’t dream of. Check out the articles I’ve given links to as well as do a little Googling before you tinker. Reading for 10 minutes prior to jumping into this could save you some potential heartache. Don’t say I didn’t warn you. 
Oh- and check out my other geeky posts in the me so g33ky category found throughout my blog. Thanks!
smooches~
jEN
