I am also posting here ...
I have Elitebook 8460p i have used clover in bootable usb to install Sierra during Post Install I have also installed clover in my Hard Drive but when I Boot from hard drive no Clover screen appears instead Message comes to me please install an operating system in your hard drive.
But when I plug in USB clover screen appears and I can now easily boot into Sierra. I can't keep the USB plugged in forever please help especially rehab man because you are behind all the installation of Sierra on elitebooks / and I have followed your
guidethroughout my installation.