I am trying to install from a bootable USB containing an installer for Mac OS X El Capitan on a Mac Mini. Normally I would hold Option while booting to gain access to a screen where I can select from the bootable USB or the internal hard drive (or any other bootable disks). The problem is that I don't currently have access to an Apple keyboard.
I have tried setting the USB to the bootable volume using
bless, but that doesn't boot into the installer.
Is there a way to force the machine to boot to that selection? Perhaps certain boot flags could be set using the
nvram command. Help is appreciated.