@Macbookprodude
For Linux I'd use either the Mac flashed Radeon card (I forget the model, sorry), or use a more modern AMD card for Linux and leave the Nvidia for OFW and OS X - Nouveau can be a bit annoying.
The way I've got it done is by blacklisting the Nvidia related stuff in my Kernel boot options and I think I put a bit in my X config too - I've not got GRUB to boot to Linux without the Mac flashed card connected to a display or spoof plug though.
For Linux I'd use either the Mac flashed Radeon card (I forget the model, sorry), or use a more modern AMD card for Linux and leave the Nvidia for OFW and OS X - Nouveau can be a bit annoying.
The way I've got it done is by blacklisting the Nvidia related stuff in my Kernel boot options and I think I put a bit in my X config too - I've not got GRUB to boot to Linux without the Mac flashed card connected to a display or spoof plug though.