I purchased a 7750 with no OS since I have my own licensing, Ubuntu is installed by default. I disabled secure boot, tried Fastboot on both Thorough and Auto, set USB as the first device in the boot sequence. I created the bootable USB in Rufus, partition scheme GPT, target system UEFI (non CSM) etc. However all I get is the same message "No media present" and it blows right past the USB drive and boots Ubuntu. What am I missing here?