I have a 2008 Macbook Pro that I installed linux on. I wiped the drive and installed from a USB drive. Now the system boots up to the linux grub menu, but dies when trying to launch the OS. Now I have no way to reinstall linux or get back to the OS X recovery screen. Nothing happens when I press Command R or any other key combination after power on. I just get the linux grub menu. Any ideas how I can get the system to allow me to boot from the USB?