I recently installed Ubuntu 12.04.2 64-bit on my laptop (Asus F501A), configured to dual boot with Windows 8, following the instructions given at https://help.ubuntu.com/community/UEFI. After installing, Ubuntu worked perfectly, however I could not access Windows from GRUB, giving the errors "unknown command 'drivemap'" and "invalid EFI file path". I ran boot-repair with the recommended repair, and this added extra Windows options to GRUB (Windows UEFI bkpbootmgfw.efi and Windows Boot UEFI loader), but these do not work either, giving errors "no such device: FACC-1C23" and "file not found".
Paste of the second attempt at boot-repair (which made no apparent changes) is at http://paste.ubuntu.com/5685009/. Secure boot and fast boot are both disabled. The drive I installed Ubuntu on is an external hard drive seperate from the one Windows is installed on, if that makes a difference.
Please advise a fix. Thanks in advance.
EDIT: In case it helps, I found the paste of my first attempt at boot-repair: http://paste.ubuntu.com/5684961/.