Repair EFI Bootloader?

Question

I'm aware there are other topics on this subject, but i've tried the fixes to no avail, hence making this post.

So I had a 1TB HDD with Windows 8.1 installed along with a partition with a recovery sector on. I shrank the HDD by 200GB and installed Linux Mint 13 on it. Turns out Linux Mint 13 had a bunch of driver issues, so I burned Linux Mint 16 64bit to disk and chosen to 'Replace Mint 13 with 16'.

Linux Mint 16 now booted into Linux mint but left no option to boot into Windows 8.1.

So I tried the following:

Booting from the Windows 8.1 disk, going to the command prompt and using:

bootrec /fixmbr
bootrec.exe /fixboot
bootrec.exe /RebuildBcd

No luck.

Then I tried:

DISKPART > list disk

Disk ###  Status   Size  Free   Dyn  Gpt
Disk 0    Online  931GB  923GB   -    *

DISKPART> sel disk 0

Disk 0 is now the selected disk.

DISKPART> list vol

Vol just gives me my DVD-ROM.

Can anyone help?

I'm getting pretty damn worried that my Windows 8.1 install is gone and un-retrievable.

Answer 1

Your DISKPART output, if I'm reading it correctly, doesn't include the right commands for full diagnostics. (I'm not very familiar with that tool, though.) That said, my suspicion is you've got a boot loader problem, not a disk partitioning problem. Your attempts to recovery with bootrec might have worked on an old BIOS-mode installation, but you've almost certainly got an EFI-based computer for which those commands are inappropriate.

I recommend you attempt recovery as follows:

1. If you haven't already done so, disable Secure Boot in your firmware.
2. Download the USB flash drive or CD-R version of my rEFInd boot manager.
3. Prepare a boot medium with rEFInd.
4. Boot to the rEFInd boot medium. If my hunch is correct, you'll see at least one boot option for Windows and at least one for Linux.
5. Test these boot options. With any luck, you'll be able to boot both OSes.
6. If you can boot both OSes, boot Mint and install the Debian-package version of rEFInd. This should solve your problem, since you should see rEFInd appear whenever you boot.

If you want to keep Secure Boot active, you can do so, but you'll need to jump through some extra hoops.

Alternatively, you can try the Boot Repair tool. If you're lucky, it will fix the problem a little bit more easily than the preceding procedure; but I'm recommending the above procedure because it's risk-free up to step #6; until then, you won't have done anything to change your system, and by the time you hit step #6, you'll be pretty sure that rEFInd will work (or you'll know that it won't and can abort the procedure). Boot Repair, OTOH, is more of a leap of faith; you run it and hope that it does the right thing, with no evidence that it actually will do the right thing. Given the uncertainty of your situation, that's a bit too great of a leap for me to recommend it.