Ah okay. I will check this. The benefit I am hoping for is to have the incredible read/write speed of the m.2 ssd with thhe system drive. Faster startup, working in programs, etc.. Maybe I am missing something? I did get it to work as an external drive and the speeds were as I was expecting.
Currently I am having trouble installing 10.13. I have deleted the driver from /Library/Extensions but still get the kernal panic on shutdown. For HS the mac pro needs the Firmware update first which requires the computer to shutdown. Problem is that the kernal panic seems to force a restart. Does anyone have a tip on how best to proceed?
I am sorry to tell you that the "faster startup" etc mainly comes from the high IOPS, not sequential read / write speed. As you can see, the boot time has virtually zero improvement by moving from SATA II to PCIe 2.0 x2. The extra bandwidth available only benefit the sequential speed, not IOPS. I never ever see any consumer SSD has a random 4K read speed that can saturate a SATA connection yet. And this is the single most critical factor that make you able to "feel" how fast the computer is (responsiveness). Of course, if you boot a SSD from a USB 2.0 connection, than the limited bandwidth is a problem. But in general, bandwidth has no effect on boot time or apps loading time etc. And this is the reason why a 1000MB/s HDD RAID array unable to give you 2x SATA SSD's (500MB/s) boot time (or apps loading) performance.
Also, m.2 is just the form factor, nothing to do with the SSD speed, a m.2 SSD can still connected via SATA connection and limited to SATA speed.
If purely "fix" the firmware update. You can simply install a clean Maverick on another bootable drive and do it there. I believe it's easier than try to fix your current issue.