Linux is a kernel. It runs the PID 1 process with root permissions. It doesn't ask for anything. The PID 1 process might, though. So it depends on userland. The

Linux is a kernel. It runs the PID 1 process with root permissions. It doesn't ask for anything. The PID 1 process might, though. So it depends on userland. Then, you can parametrize the kernel with the "init=..." boot option and specify which PID 1 process you'd want. Indeed, the easiest way to get root access is to set that kernel parameter from boot loader - if it allows you to. Which about every default boot loader does. Just set it to a shell and be aware that userland might be a bit picky because you didn't set up a proper session yet.