Comment 36 for bug 1090829

How I corrupted the ubuntu directory:
On a Toshiba Satellite S855 with Windows 8 preinstalled and Secure boot enabled, successfully installed 12.10 64b to a 4G stick, without making a efi partition on it. This created a good EFI/ubuntu directory on the hard disk, but left the EFI/Boot directory containing ony a grub.cfg file to boot the stick (so Windows would no longer boot), (although the 4G stick would boot).
  In this condition, I then installed 12.10 to a previously freed up space on the hard disk, which failed at the bootloader part, but
did end up in a condition which Windows booted. Tried again to install to the 4G stick, this time with an efi partition on the stick, which failed with the "grub-install dummy" error. Looking at the EFI with ls -l, the ubuntu directory just showed a name the "d" for directory, and all else appeared as "?"s. Apparently, the second (or maybe third) install of Ubuntu corrupted the ubuntu directory in the Windows EFI directory,. Examining the failed stick, the /etc/fstab file refers to the hard disk's EFI partition (by UUID), not the one on the stick (which was empty).