Simplify the following text for a Grade 8 native English-speaking person.
Original: This normally takes the form of a graphical menu , although if this is not available or the user wishes further control , GRUB has its own command prompt , where the user can manually specify the boot parameters .
Simplified: If this is not available , or the user wishes direct control , GRUB has its own command prompt . The user can then manually specify the boot parameters .