1

I have a UEFI system and two drives: one with Windows 10 installed( and with a lot of stuff on it, so I'd rather not have to reinstall windows) and one on which I'd like to install Ubuntu.

At first I tried installing ubuntu on the other drive and unplug the windows drive when I used ubuntu ( I had only the drive I want to install Ubuntu on plugged, so I installed it using the "erase everything and install Ubuntu" option), but when I boot into ubuntu it overwrites the windows bootloader, and to boot into windows again I have to reset the bootloader with an installation drive, which is really annoying.

So I tried having both drives connected at the same time and dual booting through the windows bootloader( with a software called easyBCD on windows), but with this method it's ubuntu that doesn't boot. So I wanted to know if there's a way to make windows boot through grub while having the two OSs' installed on different drives( I'm willing to reinstall Ubuntu, if necessary).

2 Answers 2

2

Selectively unplugging one disk or another is a trick that some people used in the BIOS era, but EFI's design makes this approach less useful. This is particularly true for some computers, which may erase boot manager entries when they're found to no longer point to valid boot loaders, which of course will be true when you unplug a disk to which they point. Thus, I strongly recommend against using this procedure when using an EFI-based computer.

The last I heard, EasyBCD was useless, or nearly so, on EFI-based computers. (That said, I haven't looked into it recently, so it could have changed.) Note that EasyBCD is a third-party Windows tool for managing the Windows boot loader and boot manager, which is known as the BCD. The BCD itself can be used to chainload to a Linux boot loader; however, I know very little about how to configure it to do so.

Most Linux users run GRUB 2 as their boot manager under EFI; however, other options are available, as outlined in this question and its answers. Ideally, the simplest procedure to get GRUB 2 working is:

  1. Install Windows
  2. Install Ubuntu

The Ubuntu installer should detect Windows and add it as a boot option to the GRUB menu. Juggling disks, skipping the GRUB installation in favor of something else, and other advanced trickery is most likely to cause new problems. That said, there are cases when you might want to take an alternative path, such as if you dislike GRUB and want to use something else. In such a case, though, you should research the issue before beginning.

Also, note that neither Windows nor Ubuntu should delete the other's boot loader. What both will do, however, is to place their own boot loader (BCD or GRUB) as the first one in the EFI's boot manager list. You can modify this ordering with EasyUEFI or bcdedit in Windows, with efibootmgr in Ubuntu, or with some (but not all) computers' built-in firmware configuration utilities. If you don't understand how all these pieces (the firmware's boot manager, BCD, GRUB, and perhaps other tools) fit together, you're likely to become confused. To that end, here's some suggested reading:

For specific advice on how to proceed, if you can boot Ubuntu right now, try doing so (with the Windows drive also connected) and then type sudo update-grub at the command line. That will re-run the GRUB configuration scripts, which should cause it to detect Windows and add it to the GRUB menu. If that doesn't work, then you need to be more specific about what's not working -- for instance, is Windows not appearing in the GRUB menu, is it appearing but failing, and if it's failing, what error messages (if any) do you see?

1
0

I just dual booted Windows 10 and Ubuntu 16.04 using the hard drive juggle and it was very easy. Make sure UEFI is enabled in your BIOS (my Gigabyte board called it "Windows 8" mode). Assuming two drives, A and B:

  1. Install Windows 10 on drive A
  2. Unplug drive A
  3. Install Ubuntu on drive B
  4. Plug drive A back in
  5. Boot up (boots into Ubuntu with no sign of Windows)
  6. sudo apt-get install grub2 (Windows will be detected and added to grub menu)

Easy peasy, no fanciness, articles, or theory required. Not to mention it's very easy to simply remove either drive and go back to a one drive system.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .