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I am trying to add Ubuntu to the Windows boot manager in Windows 8.1. I have tried using easyBCD to do this but as I am booting in UEFI mode it fails to work. Is there a way to manually add it in using bcdedit or another piece of software? I tried using easyUEFI but had no success. I don't really want to use GRUB2 as my main boot manager.

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    Does one time boot key like f10 or f12 work to choose what to boot? Is Ubuntu installed in UEFI boot mode? If it is have you tried this. bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi I think that uses UEFI one time reboot which seems to work on some systems, but forces a warm reboot. – oldfred Apr 6 '15 at 21:17
  • I have tried using that bcdedit line of code and it just changes the boot manager to be grub2, I would ideally like to use the windows boot loader – stuart194 Apr 6 '15 at 21:26
  • If I use a one time reboot mode it works fine the problem I am having is creating the option on the windows boot manager – stuart194 Apr 6 '15 at 21:34
  • When you reboot with the BCD entry, you will get grub menu as grub is both a boot manager or menu and the boot loader. UEFI is a boot manager or menu and EasyBCD modifies Windows to be a boot menu. You end up with so many menus that you are not sure where you are at. – oldfred Apr 6 '15 at 23:24
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First, some terminology:

  • A boot loader loads a kernel into memory and executes it.
  • A boot manager presents a menu that lets you select which OS to boot.

GRUB does both jobs for Linux, although it can't load a Windows kernel directly; to boot Windows, GRUB redirects to the Windows boot program. Likewise, the Windows boot program cannot directly load a Linux kernel (but see below) and so is a poor choice for booting Linux, although I believe that it (like GRUB) includes both boot loader and boot manager functionality, and so can (theoretically) be configured to redirect to GRUB. Knowledge of how to do this under BIOS is fairly widespread, but people who've managed to do it under EFI are relatively rare.

One significant twist on this is that since version 3.3.0, the Linux kernel has included its own EFI boot loader, so an EFI boot manager can launch a Linux kernel, even if that boot manager doesn't have Linux boot loader capabilities. In fact, rEFInd and gummiboot rely on this feature; these programs are both technically boot managers, but they can launch a Linux kernel that has an EFI stub loader. In theory, the Windows boot program might be able to launch Linux in this way. In practice, this would be difficult to get working, since the kernel needs parameters passed to it in order to work, and configuring the Windows boot program to pass the right parameters is likely to be even trickier than getting it to pass control to GRUB. I've never heard of anybody even trying this, much less getting it to work.

On this forum, you're much more likely to find expertise and advice on using GRUB, rEFIt, rEFInd, or gummiboot as your primary boot manager than on using the Windows boot program as a boot manager. If you really must use the Windows boot program as a boot manager, I recommend you ask on a Windows forum.

  • Ah yes I see I made a mistake in the question. I do understand the difference between a manager and a loader. Apparently bootnext will add GRUB successfully to the windows boot manager when booting in EFI mode. I have also seen claims that easyBCD supports EFI but I believe these false. – stuart194 Apr 8 '15 at 9:08
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The Windows Boot Manager in UEFI mode will not boot other operating systems or legacy Windows OSes according to both Windows 10 forum and EasyBCD. So that's a no go.

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