I believe that I have messed up partitions on my 8GBYTE SD and now I get GRUB LOADING 1.5 eRROR 17... AND BOOTUP PROCESS GOES NO FURTHER. I need to edit grub. I have used "esc", and "shift" to stop grub loading but to no avail. Any thoughts out there? What key combination should I use. Note: I was running Ubuntu. I have already tried to boot from usb with same results.