[TUTORIAL] How to bypass the CPU downclock when using your MBP without a battery
A couple of months ago my mid 2010 13'' Macbook started failing to recognize the battery. When I took it to an authorized apple assistance, they told me I'd have to change the entire logic board in order to make it work again (which would cost me around $900, here in Brazil).
The problem is that the newer MacBooks have a specific CPU power management that down clocks the CPU for safety reasons when the battery is not detected, making it barely usable. Then I tried to run Windows 7 and the machine worked like charm! When I found this was a software related issue then I knew that there has to be a solution to make it work with OS X.
After a some research I finally found a way to fix that. If you're OK to use your MBP always connected to the AC Adapter, then that's the cheapest and easiest solution for you!
Let's get to it...
1- First download these two kext files:
NullCPUPowerManagement (32-/64-bit)
2- Go to /System/Library/Extensions
3- Make a backup of AppleIntelCPUPowerMangement.kext and AppleIntelCPUPowerMangementClient.kext and then delete it from this folder
4- Add here the two kext files you've downloaded earlier
5- Open Terminal and do the following:
cd /System/Library/Extensions
sudo chown -R root:wheel SleepEnabler.kext
sudo chmod -R 755 SleepEnabler.kext
sudo chown -R root:wheel NullCPUPowerManagement.kext
sudo chmod -R 755 NullCPUPowerManagement.kext
6- Reboot and you're done!
If the computer doesn't boot, do this:
1. Hold down the option key while powering on
2. Choose [Recovery HD]
3. Open Terminal
4. Do the following:
cd /Volumes/[volumename]/System/Library/Extensions
rm -rf SleepEnabler.kext
rm -rf NullCPUPowerManagement.kext
5- Restart
6- Put AppleIntelCPUPowerMangement.kext and AppleIntelCPUPowerMangementClient.kext back in the /System/Library/Extensions folder
Voilá!
The fans are still on high, but the slowdown is totally gone. Is good to use a software like CoolBook to manage the energy resources from now on.
I hope it helps whoever is out of Apple Care to save some money!
Comments
Thanks for the write up. But it didn't work for me. I'm on a mid-2009 Macbook Pro on OSX 10.7.5. Ended up just buying a new battery.
Actually, just restored a cloned copy of my OS from when I didn't have a battery and my computer is again downclocked (even with a battery installed!). I checked and realized I had the NullCPUPowerManagement kext still in my extensions folder. So it's weird; it's causing my computer to ignore the normal Power Management and to keep whatever setting state was on there before. So it looks like there's a record on the software side. I know you were using Coolbook and with that program you can change the processor speed so maybe that's why you were successful. You neutralized the original Power Management and had Coolbook set the speed for you. Unfortunately, I am on Lion and Coolbook doesn't support that.
Anyway, I removed the NullCPUPower Managment kext and my speeds are back up. And also, for anyone else trying to get this to work, the record wasn't in the SMC so it's gotta be somewhere on the OS system. I think if you find where, you'll have better luck.