Bootable USB installer of Sierra GM and public releases To make the bootable usb of Sierra GM and public releases format an 8 GB (or preferably 16GB) USB3 drive which should be called Untitled and formatted as Mac OS Extended (Journaled). The installer should be called Install macOS Sierra.app and should be in your Applications folder. Run this in terminal and wait about 20 minutes: sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ macOS\ Sierra.app --nointeraction
Also, reverting core storage still works in Sierra. If the installation creates a core storage logical volume you can revert it to get partitions back to normal by running these 2 commands in terminal. diskutil cs list and then diskutil coreStorage revert lvUUID where lvUUID is the last lvUUID reported by the previous Terminal command. Then restart for everything to get back to normal after you have run these commands in Terminal. This is good if you want the recovery partition to show up in the startup manager you get when booting up with the option key.
There is no need for all this. Just run the command below using whatever your OS volume name is in place of the default Macintosh HD. Code: diskutil cs revert "Macintosh HD"
I still think you should run this to see if you even have something to revert first: diskutil cs list And if there is only 1 core storage volume you can do it a shorter way too: distil cs revert / But I prefer to do it the long way because it is more specific.