Install bootloader on USB disk

Given that the Floppy Disk is now in short supply and they were replaced by USB flash memory... can give people the opportunity to use a USB device as a bootloader? On the one hand will be able to load the main system, on the other hand this will enable more convenient testing ROS on real hardware. ROS will not affect the MBR of the hard disk, so the risk of injury will be minimal. The user will be able to boot main OS, and ROS, using USB.