How do I reinstall the SMC firmware?

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Level 1

8 points

How do I reinstall the SMC firmware?

Does anyone know how to reinstall the SMC firmware on a mid 2011 Macbook Air? This computer's fan has never turned ran above 2000rpm (on it's own). This is my first mac and I assumed it didn't have a fan since I never heard it.

It worked fine for the first year or so, although I did notice it crashed a lot while using Windows in bootcamp. It later started to crash more often on the OS X side. Things like watching youtube videos or going to websites with flash would cause it to crash. I took it into the Apple store and while their diagnostic tests said everything was fine, I demonstrated to them how youtube would overheat it and the fan would never rev up. They offered to have the logic board replaced at my cost since it was three months out of warranty. I have intstead nursed it along using Macs Fan Control.

Later, I spoke with a friend who was conviently enough a project engineer on the Macbook Air and described the symptoms to him. He said that since the third-party software would drive the fan, it wasn't a hardware problem, but that it was probably something corrupted in the SMC firmware. With that, I went back to the Genius Bar where they tried to install the SMC firmware from a thumbdrive. After it didn't work, they suggested calling Apple Care. Apple Care had me upgrade to Mavericks, which caused it to overheat more quickly, but they didn't know how to reinstall the SMC firmware.

Does anyone here know how? Trying to install the current one doesn't work. Thanks

MacBook Air (13-inch Mid 2011), Mac OS X (10.7.5)

Posted on Apr 7, 2014 4:30 PM

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Answer 1

Apr 7, 2014 4:34 PM in response to doneso

reset, not reinstall.

SMC reset

Shut down the computer.
Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
Release all the keys and the power button at the same time.
Press the power button to turn on the computer.
Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.

About the SMC Firmware Updates

http://support.apple.com/kb/ht4117

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Answer 2

doneso Author

Level 1

8 points

Apr 7, 2014 4:58 PM in response to doneso

To be clear, I am not looking to reset the SMC. Resetting the SMC was one of the first things I tried, and something I have done several times.

My Apple engineer friend was very clear that resetting a bad SMC install would not fix the problem.

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Answer 3

Apr 7, 2014 5:06 PM in response to doneso

http://support.apple.com/kb/HT2213?viewlocale=en_US

About the Firmware Restoration CD (Intel-based Macs)

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Answer 4

doneso Author

Level 1

8 points

Apr 7, 2014 9:50 PM in response to PlotinusVeritas

I take it back, didn't solve the problem. Apple doesn't have a firmware restoration CD for anything after the 2010 Macbook Pro. I can download the SMC and put the .dmg on a CD, but it won't load it per the instructions you posted.

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Answer 5

doneso Author

Level 1

8 points

Apr 9, 2014 3:59 PM in response to doneso

I've reposted this question here since this thread is erroneously marked "solved."

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Answer 6

Apr 9, 2014 4:18 PM in response to doneso

You marked it as such. 😊

How to handle OS X firmware updates that won't install

After following these steps, try rebooting again to see if the issue has been resolved. If not, remove any residual traces of past update attempts by opening the System > Library > CoreServices > Firmware Updates directory and moving any items in this folder to the desktop. Then try downloading the relevant updater manually from the Apple Support Downloads page and run it. You can search for the update on this page or, for more recent updates, you'll see them listed at the top of the page.

As a last resort, you can try installing the firmware update from a fresh OS installation. Attach an external hard drive and reboot the system with Command-R held down to load the recovery drive. Then install a fresh copy of OS X to the drive. This will ensure a factory-default software environment in which you can try applying the firmware update. After the firmware update is installed, you can open the Startup Disk system preferences and select your main boot drive again.

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