I've successfully curated an NVMe kext for my Samsung 960 M.2 NVMe SSD drive using the Github process. You can see my efforts here. But there's one more thing I need to do, and that's to add the NVMe kext to my Recovery HD so that when I boot from it I can mount/read/write/repair my NVMe SSD/HDD Fusion Drive (FD). Without it I can't see the NVMe volume, therefore I can't mount the FD if I ever needed to (the NVMe is in a FD with a 2TB WD Black Caviar HDD). I do have a separate HDD with macOS and the NVMe kext installed, so I can work from that instead, but I want my Recovery HD to be able to mount/read/write the M.2 SSD. I followed this method to try and add the NVMe kext to my Recovery HD, but it hasn't worked - it doesn't/can't see the NVMe or FD (the HDD shows up on its own but obviously doesn't show any files - it would be dangerous to work on it as that would no doubt destroy the FD). The good thing so far is I haven't broken the Recovery HD (phew). Does anyone have any experience in adding kexts to/modifying the Recovery HD so I can make this work? I realise that future macOS updates will probably break the Recovery HD.