History: I successfully installed xubuntu 12.10 onto my Asus UX31A, which has win8 pre-installed, UEFI, 256GB SSD, GPT. I did this by disabling Secure Boot & enabling CSM in UEFI settings. GRUB 2 installed and I ran the ubuntu boot repair tool (from usb) to correct the known bug which caused win8 not to load.
Later within win8, an MS update led to a major failure of my win8 system, requiring to do a system refresh (by pushing F8) using recovery partitions. This then led to win8 overwriting GRUB2 with its own MBR and I can now no longer access my xubuntu 12.10. (damn you MS!!)
I do not know the source of the win8 error, but fear GRUB2 perhaps clashed with an MS update for its own bootloader. (of course, it may have been a win8 software compatibility issue.)
I now wish to regain access to my xubuntu. Yes, I can rerun the ubuntu boot repair tool and do the recommended repair but this will undoubtedly reinstate GRUB2. BUT, for warranty reasons, I'd prefer to retain the windows MBR whilst also reinstalling GRUB2.
So, can someone please give a step-by-step guide for a n00b like me on using the ubuntu boot repair tool's advanced settings to purge grub2 (if necessary), reinstall grub2 and then restore the MBR. I am simply afraid to **** the whole thing up and find no guidance on this stuff anywhere!
Thanks in advance!