4

I was having some issues with my mac so I reset NVRAM by holding ++P+R.

The problem is that this laptop does not chime when NVRAM is reset, so I'm not sure if NVRAM was indeed reset.

How can I find out whether NVRAM was reset?

Is there some terminal command that shows when NVRAM was last reset?

  • Laptop: 2017 MacBook Pro
  • OS:MacOS High Sierra
  • This page at OSXDaily has a wealth of NVRAM information. – IconDaemon Apr 23 '19 at 14:53
  • It has ways of clearing nvram, but not ways for checking the status. – octavian Apr 23 '19 at 15:01
  • If it reboots again, it cleared. I've never had a Mac laptop, so I don't know how obvious that is without a chime. – Tetsujin Apr 23 '19 at 15:19
  • nvram -xp gives you an XML file of NVRAM's key/value pairs. After running sudo nvram -c to clear the NVRAM, the XML file given by nvram -xp will be empty. That's how you can verify that you've reset it. Then, you have to restart for the reset to become effective. – Gumby The Green Mar 8 at 23:50
3

Doesn't appear to be a direct way to do this. Part of the problem is that your changes to the NVRAM, if you were to clear it (nvram -c), will not take effect until after a reboot.

You could try this method which will perform a side-by-side diff of the contents of NVRAM prior to running a nvram -c.

For example:

$ sdiff <(nvram -xp) <(nvram -c &> /dev/null; nvram -xp) | less

If there's any changes you should see lines with vertical bars (|) which will denote lines that changed. Content on the left side will be your before and content on the right will be your after.

References

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  • It boggles the mind that there is no easy way to check that it worked, especially since thousands (millions?) of mac notebooks have faulty keyboards and the four buttons may not press correctly, even if the user has held them down as required. AND because it's a vital step in preparing to give (sell) one's device to a stranger - not something to risk! – stevec Aug 8 at 11:34

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