2014-05-31

Restoring EFI NVRAM boot entries with rEFInd and Rufus

So, you reinstalled Windows, and it somehow screwed the nice EFI entry you had that booted your meticulously crafted EFI system partition? You know, the one you use with rEFInd or ELILO or whatever, to multiboot Linux, Windows, etc., and that has other goodies such as the EFI shell...

Well, here's how you can sort yourself out (shamelessly adapted from the always awesome and extremely comprehensive Arch Linux documentation):
  • Download the latest rEFInd CD-R image from here.
  • Extract the ISO and use Rufus to create a bootable USB drive. Make sure that, when you create the USB, you have "GPT partition scheme for UEFI computer" selected, under "Partition scheme and target system type".
  • Boot your computer in UEFI mode, and enter the EFI BIOS to select the USB as your boot device
  • On the rEFInd screen select "Start EFI shell".
  • At the 2.0 Shell > prompt type:
    bcfg boot dump

    This should confirm that some of your old entries have been unceremoniously wiped out by Windows.
  • Find the disk on which your old EFI partition resides by issuing something like:
    dir fs0:\efi

    NB: you can use the map command to get a list of all the disks and partitions detected during boot.
  • Once you have the proper fs# information (and provided you want to add an entry that boots into a rEFInd installed on your EFI system partition under EFI\refind\refind_x64.efi), issue something like:
    bcfg boot add 0 fs0:\EFI\refind\refind_x64.efi rEFInd
    Note: If needed you can also use bcfg boot rm # to remove existing entries.
  • Confirm that your entry has been properly installed as the first option, by re-issuing bcfg boot dump. Then remove the USB, reset your machine, and you should find that everything is back to normal.
NOTE: Make sure you use the latest rEFInd if you want an EFI shell that includes bcfg. Not all EFI shells will contain that command!

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