thanks for your reply!
yeah i wouldn't be able to boot without a nvme driver.
I followed your github page to install (of course with NVMeGeneric.kext removed first) HackrNVMeFamily in /S/L/E, or in CLOVER/kexts/Other
both led to same result, that boot process failed at early stage with "Still waiting for root device"
Did I miss something for the installation? I read something about Sierra adds support for using NVMe as a boot device. Does it imply that HackrNVMeFamily doesn't support boot in El Capitan?
Back to what you've mentioned, I've tried to boot into another El Capitan install on a usb SSD, to get the ioreg. Please have a look at the new ioreg files (before and after loading HackrNVMe manually). Thanks!
Both ioreg show no HackrNVMe loaded.
Make sure you created it correctly.
Make sure you removed IONVMeFamily.kext.
Make sure you installed HackrNVMeFamily correctly.
Note: There is growing evidence to suggest Pike's patches do not work with (certain?) Intel SSDs. You should purchase a Samsung 950 Pro NVMe.