This method will work for any motherboard with an Intel 6-series chipset and above and has support for an AMI UEFI BIOS.
Disclaimer: Win-raid, Tweaktown and me are not liable or responsible if you brick your motherboard. Do this at your own risk. You have been warned.
1. Download your vendor's Z97 BIOS such as ASUS, Gigabyte, EVGA and etc i.e. if you have a Gigabyte Z77 Motherboard then download Gigabyte Z97 BIOS. For X79 you can try the Z97 or X99 modules to see which one works.
2. Download MMTOOL4 here: https://onedrive.live.com/?id=5014229B9E752333%2122667&cid=5014229B9E752333&group=0&parId=5014229B9E752333%21998&authkey=%21APlNBZ5ptxzEbKY&action=locate
3. Load the Z97 or X99 BIOS in MMTOOL4.
4. Click on the extract tab.
5. Go the Extract FFS Option
6. Choose the option 'Extract Uncompressed'
7. Find the various Modules named Nvme, NvmeSmm, NvmeInt13.
8. For every module press Extract.
9. Press on the button extract.
10. Exit MMTool4.
11. Open your own Motherboard BIOS in MMTOOL4.
12. Find the module named CSMCORE.
13. In the insert tab and in the Insert FFS Options and choose the option Insert Compressed.
14. Load the NVMe.ffs module click on the button insert.
15. Repeat step 12 and 14 again for NvmeSmm and NvmeInt13
16. Save the modded BIOS and flash it.
Thanks to Fernando, lordkag, CodeRush from win-raid for all the help, research and development. I used their works for the tutorial.
Please read this thread for current development: [Discussion] NVMe BIOS Modules and NVMe Support
Please read this important message from lordkag: RE: Full NVMe support for older Intel Chipsets possible! - 11
Fernando's feedback to lordkag: RE: NVMe-Support: Only drivers or EFI-modules necessary? - 8
Another person's feedback: RE: [Discussion] NVMe BIOS Modules and NVMe Support - 12
I currently don't have an NVMe SSD to test so I'm relying on secondary sources.