I put Fedora on my 2012 MBP Retina. I made a USB key, iirc with the Fedora USB image tool, then plugged the USB key into the MBP and held the Option key as I po

I put Fedora on my 2012 MBP Retina. I made a USB key, iirc with the Fedora USB image tool, then plugged the USB key into the MBP and held the Option key as I powered it on. USB key shows up as a bootable option.