Ubuntu – Dual Boot with Windows 8 UEFI – Ubuntu/GRUB Being Bypassed

13.04dual-bootuefiwindows 8

I recently got a Dell Inspiron 13z with Windows 8. I decided to dual boot Ubuntu.

After install, it was booting straight into Ubuntu, with no GRUB menu showing up. No problem. I just ran boot repair and everything seemed to work fine. (Here's the output, btw: http://paste.ubuntu.com/5891478/)

Then I booted into Windows. Now I can't seem to get back into Ubuntu. I tried disabling Fast Boot by running REG ADD "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Power" /V HiberbootEnabled /T REG_dWORD /D 0 /F in PowerShell as Administrator. Even now, GRUB is still being bypassed somehow.

What should I do?

EDIT: I tried reinstalling GRUB by booting a LiveUSB and following this: https://superuser.com/questions/376470/how-to-reinstall-grub2-efi. Unfortunately, that didn't work.

Best Answer

The Boot Repair tool isn't 100% reliable. The problem you seem to have run into is that Boot Repair is rather over-enthusiastic about juggling boot loader files. Specifically, Boot Repair renames the Windows boot loader and installs a copy of GRUB in its place; however, this "repair," in addition to being terribly confusing, is sometimes undone by Windows -- Windows sees the change and (quite reasonably) re-installs its own boot loader. What's more, this "repair" is seldom necessary; the tool just applies it in a scattershot approach with a bunch of other "repairs" in the hopes that it will be useful. Unfortunately, sometimes it's not, and it can cause follow-on problems.

I recommend you try this:

  1. Back up the contents of your EFI System Partition (ESP; your /dev/sda1). This will serve as a fallback in case you make matters worse.
  2. Re-run Boot Repair, but click the Advanced Options item and check the Restore EFI Backups option before proceeding. This will undo some of Boot Repair's changes.
  3. Reboot and test both Windows and Ubuntu. There's a good chance that everything will work; however....
    • If the system starts booting Windows directly, launch an Administrator Command Prompt window (not a PowerShell; it won't work) and type bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi.
    • If the system starts booting Ubuntu directly with no option to boot Windows, install my rEFInd boot manager. Installing the Debian package is the easiest way to do this. rEFInd tends to be more reliable about launching Windows than is GRUB, so this may well fix the problem.
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