Can be. A bootloader is just a baremetal application, so called not by architecture but its primary purpose of loading much larger images, jumping to it and not

Can be. A bootloader is just a baremetal application, so called not by architecture but its primary purpose of loading much larger images, jumping to it and not coming back. If the CPU is coming back, it's called a monitor program, if it's going back and forth, it's a supervisor, or a kernel. Old/mainframe folks sometimes call operating system kernel a supervisor program. Theoretically it should be possible to flash Linux Kernel onto BIOS Flash ROM to directly load and run it from there. But x86 being x86, you also have to have bunch of circus tricks to initialize motherboard and to get out of 16-bit 8086 compatible mode and to load Kernel from disk, in such hypothetical Kernel image. BIOS/UEFI and bootloader each do parts of those.