What is Kext

Every new Mackintosh and Hackintosh user must understand the role of kext but what is kext actually….? It is an abbreviation for kernel extension, it is basically the Mac OS equivalent to a Windows driver,in simple words it is similar to the device driver which inject device ID’s and Vender ID’s to work or perform the hardware properly.

What is KEXT?

KEXT stands for Kernel Extension, this means that whatever needs to run in the kernel (OS core) environment can be written as extension and then loaded, even after the OSX has finished loading, this mostly answers the needs for hardware drivers.

Where are kext located?

Basically kext are not the folder or the files and they are located at
root=Root directory of you OS X 
From OS X Leopard 10.5.x to OS X Yosemite 10.10 the kext location is not yet changed 

How to Install a new kext ?

There are two ways to install new kext. One is to manually install and second is by install using 3rd party software like Kext Utility,kext helper,Using Kext Utility is is quite simple to install the new kext 
To install new kext open Kext utility and drag the kext 
Kext Utility
 How to Install a new Kext?
Open terminal 
cd /System/Library/Extensions
mv KextName.kext KextName.bak  
(where kext Name stands for the kext you want to replace) this will rename the kext and this way back it up, which is highly recommended, it is very important to follow this step, it had saved my OS many times
cd /path/to/new/kext (put your downloaded kext path here)

cp -R KextName.kext /System/Library/Extensions
Next you need to fix permissions so the kext can be executed by OS user (root/system)

cd /System/Library/Extensions
chmod -R 755 KextName.kext
chown -R 0:0 KextName.kext   (this will set the ownership on files to system user (root))
rm /System/Library/Extensions.mkext   (this will reset all kext caching done by OSX)

How to uninstall a problematic Kext?

Open terminal

cd /System/Library/Extensions

rm -rf name of the kext.kext
sudo rm -rf /System/Library/Caches/*
shutdown -r now

But what if i am not able to boot my OS X and want to delete the problematic kext on this situation you have to boot with Single user mode “-s” 

Macintosh user hold the command key before boot the OS X and type “-s”
Hackintosh user simply have to add this flag on chameleon boot menu 
To uninstall the Problematic kext to avoid the Kernel Panic see my older guide