As the Japanese say ( I live there ) when they have accomplished something very satisfying .. . やた ! = Yata ! = I ( bloody ) DID IT ! It's 2:20 am here in Japan and I just booted from a USB 3.0 card in my 4,1>5,1 cMP in the cMP USB 2.0 front port .. to Sierra 10.12.6 to my brand spanking new Samsung 960 EVO 256 Gb M.2 First a very, very, very big "Hats OFF to Foxfoobar ! " I'm totally in awe of your computing skills. What really surprised me was that from EFI boot login screen the total boot to Sierra desktop was around 20 seconds ! CS 6 Photoshop loads insanely fast from the 960 EVO. Also surprising was that the only about 69mb was loaded into the USB 3.o stick. Next time I'll use a 4Gb stick. I could have done this procedure with Hi Sierra 10.13.4 but opted to use Sierra 10.12.6 because it is a virtually finished product .. good for practice and of course I backed up everything prior to starting anything. When Hi Sierra is finalised I will go through the procedure again with it. Sierra was a longer setup as first I had to get Sierra 12.12.6 seeing the 960 EVO but in the end it wasn't that hard thanks to another budding Genius JedNZ Kudos to JedNZ ! Post # 43 https://forums.macrumors.com/threads/mac-pro-best-drive-configuration.2006863/page-2 I have Hi Sierra on a ¥7,000 El Cheapo stashed away in my DVD compartment. . that was the only other drive besides the Samsung 960 EVO and the USB 3.0 stick in the cMP at boot time. Finally I'm incredibly happy & satisfied with my decision to buy my 4,1 2009 dual quad 2.93Ghz cMP. My gratitude also extends to the Macrumors mods & team. ======================================================= I worked very painstakingly in following Foxfoobar's instructions to the point where I put a space between each of the Terminal commands; many cMP owners are not what one would call " Terminal savvy " including myself . I hope this example helps.