Hi Guys this problem has been driving me nuts but have finally found my answer. I have an Nvidia 660Ti graphics card.
Firstly edit AppleGraphicsControl.kext and add your Mac Board ID. Open config.plist with Clover Configurator click on SMBIOS and read what Board ID says.
Then edit AppleGraphicsControl.kext and add your Mac board ID, don't forget to add none. I use MacBookPro9,2 and it was not listed. Once I added it in saved it and loaded it with kext wizard. and rebooted my graphics card was showing correctly.
I also added in Clover boot loader CsmVideoDxe-64. In config.plist under "System Parameters" I added NvidiaWeb=true. Under boot Arg I did not add Nvda_drv=1
Hope this info helps
This worked for me, though I did NOT add the "CsmVideoDxe-64" file into Clover. I am running Clover 3763, configured as an iMac 12.2 with a nVidia GTX 650 Ti Boost. Simply edited the "AppleGraphicsDevicePolicy.kext" within the Plugins section of the "AppleGraphicsControl.kext" under S/L/E, adding the below to the Info.plist file within;
<key>Mac-942B59F58194171B</key>
<string>none</string>
I expect though that this will again be a problem in future updates, so would be good to know if it can be patched at boot time with Clover?
Update to include below note.
NB: I first took a copy of the kext, made the necessary updates and then reinstalled using "kext utility" per bilbo123's original post, I am sure KextBeast can be used to install updated kext too.