I began to install Ubuntu, but got a message about UEFI/BIOS compatibility and how I wouldn't be able to boot both.
If I install as UEFI, will I be able to reinstall Windows 7 as UEFI? Or should I just install Ubuntu in legacy mode?
bootsystem-installationuefiwindows 7
I began to install Ubuntu, but got a message about UEFI/BIOS compatibility and how I wouldn't be able to boot both.
If I install as UEFI, will I be able to reinstall Windows 7 as UEFI? Or should I just install Ubuntu in legacy mode?
This is probably a Secure Boot issue, at least in part. (Selecting the correct EFI-mode boot option may be part of the issue, too.) On the one system I've got that can handle Secure Boot, enabling it and trying to boot from a disc that can boot in either EFI or BIOS mode, but without a valid Secure Boot signature, results in a BIOS-mode boot, even if I tell the computer to boot in EFI mode. This behavior exactly matches your description of what's happening to you. Furthermore, you say this is a new computer with Windows 8 installed, which means that it almost certainly shipped with Secure Boot active.
If I'm right, you have three options for how to proceed:
For more information on all of these approaches, see this Web page I wrote on the subject. Note that the Web page says nothing about OS installation. Most of the issues and procedures would be the same for OS installation as for anything else, but modifying files on an installation CD is trickier than modifying files on a USB flash drive, so keep that in mind when you're considering your options.
Addition: I can think of a number of reasons why you might be getting an "Operating system not found" message even when booting in EFI mode with Secure Boot disabled. I suggest you check the following:
EFI/BOOT/bootx64.efi
. (Case shouldn't matter; but see below.) This is the boot loader file. If it's absent, the disk won't boot. You'll need to figure out what happened to the file and restore it.You could also try booting something else in EFI mode. One possibility is rEFInd, which is an EFI boot loader that, if you can get it to boot, it may be able to detect and run the Ubuntu installer's boot loader. There's a CD image of rEFInd, but that really is a CD image, not a USB image. To create a USB image, you'd need to download the binary file and install it manually. Tip: There's a new install.sh
script that's available here. (It's destined for the next release, but that release isn't finalized yet.) This version of the script includes a new option, --usedefault
, that can be used to help create a bootable USB flash drive. You'd use it like this:
sudo ./install.sh --usedefault /dev/sdc1
This example should create an EFI-bootable USB flash drive on /dev/sdc1
, provided that partition is an ESP on the USB flash drive. Note that you must partition the disk and create a FAT ESP before running install.sh
.
One more possibility is to install in BIOS mode and then sort it out later. You can install rEFInd, gummiboot, or an EFI-enabled version of GRUB after installing in BIOS mode. You might need to jump through some hoops with renaming boot loaders to get things working, but if you can't get your installer to boot in EFI mode, this may be your only option.
You've got a BIOS/CSM/legacy-mode installation of Windows, but you booted the Ubuntu installer in EFI/UEFI mode. The two modes can be made to coexist, but doing so is tricky. It's generally better to boot the Ubuntu installation medium in BIOS mode. Broadly speaking, this can be done in either of two ways:
EFI/BOOT/bootx64.efi
for an x86-64 system.) If you're booting from an optical disc, adjusting the boot loaders on it is much more complex.Note that these two approaches are intertwined; you can't boot to BIOS mode if the boot medium lacks a BIOS-mode boot loader, no matter how hard you try. Thus, if you have trouble controlling the boot mode, you may need to re-examine how you prepared the Ubuntu installation disk, since that method might have omitted the BIOS boot loader. Also, some computers offer such poor boot managers that you may not be able to control their boot modes except by adjusting the boot medium.
If you need more information on this subject, see this page of mine. Note that it's written mainly for people who have EFI-mode Windows installations and who might be accidentally booting the Linux installer in BIOS mode, which is the opposite of your problem; but the basic information is still relevant.
Another way to solve your problem is to convert your BIOS-mode Windows installation into an EFI-mode installation, as described on this blog post. You could then install Ubuntu in EFI mode. In the long run, this may be a cleaner solution than booting both OSes in BIOS mode, for the reasons described on my CSM page; however, this approach will be much harder and riskier in the short term. Thus, it's probably better to stick with a BIOS-mode Ubuntu installation for now unless you have some other compelling reason to make the switch.
Best Answer
To prevent needless complication, I would advise that you install Ubuntu in the same fashion that Windows is currently installed.
So, if Windows is installed as UEFI, it would be best to install Ubuntu under UEFI such that you don't need to swap bootloader modes or reinstall Windows to change OSes. Similarly, if Windows is in Legacy mode, install Ubuntu in the same.
If it really doesn't matter to you, though, I'd highly suggest using UEFI. It offers many more features that can come in handy on modern systems, and can allow for better compatibility with graphics and hardware stacks on modern systems. All in all, though, it really doesn't matter after you get past the bootloader.