Whats happening at automatic dual-boot UEFI install

[netlord]

Hi there

I have to configure an dual-boot between win8.1 and linux in uefi-mode.
Therefore i´m plan to use mint as linux-distribution.

I´ve installed win 8.1, resized the partition and booten from Mint usb-stick.
Then I started the installer and installed mint - works like a charm.

Because I have to do this on a number of machines (and I´m willing to learn) I need to know what its happening in the installer.

Obviously GRUB is installed. But where exactly? /dev/sda or /dev/sda1
How to activate GRUB instead of windows boot manager?
Is there a Install-Log where i can see this?

Thank you

[Habitual]

Welcome to LM!
If I had to guess, I'd look at the files in, or "under" /var/log/installer/

but it's just a "guess" and probably a poor one.

[Fred Barclay]

I can't tell positively tell you where Grub is installed on a UEFI computer due to lack of personal experience. On a BIOS machine it's installed by default to the boot sector of the hard drive (so usually in the installer menu you'd see an option to install it to /dev/sda--that's what you want) but for UEFI machines I believe it's installed to the /boot/efi partition if Mint is installed in EFI mode, otherwise it's installed to /dev/sda like for BIOS machines.


Grub should automatically replace the Windows Boot Manager. The fact that you ask "how to activate Grub?" tells me that the Windows Boot Manager still comes up when you start your machine, right? I suspect I know why, but to clarify, can you:
1. Still boot Windows?
2. Boot Mint from the hard drive?
3. Tell me if either Windows or Mint was installed in EFI or UEFI mode?

[fabien85]

If you are in UEFI mode, then grub is installed on the EFI system partition (ESP), which is most often sda1 (the default when a disk is formatted to GPT, though by doing things manually it's possible to put the ESP somewhere else)
The ESP is a small (100-500 MB usually) FAT32 partition where bootloaders are installed as .efi binary files.
In UEFI, bootloaders can coexist peacefully in general, so windows boot manager (bootmgfw.efi) should still exist on the partition (often in /EFI/Microsoft/Boot/). It's just that grub was registered in the firmware as the default boot entry.
You can see the boot order from your firmware interface, the grub entry should be named either ubuntu or grub, maybe even shim or mint. The windows boot entry may still be there also. You can change the boot order, so put windows before grub or the contrary.
The boot order and boot entries can also be manipulated from within Mint with a utility called efibootmgr.
I advise caution manipulating boot entries, as you can easily get your computer to not boot anything, if you dont know what you are doing. (recovery is possible but not trivial)

In the case of grub, there are also files in the linux partition at /boot/grub, in particular grub.cfg which contains the description of the grub entries.
Other bootloaders (like refind) can be more contained and reside only on the ESP, thus being more robust to filesystem corruption (except if the ESP is corrupted, but then you're screwed with any bootloader anyway).

[austin.texas]

Obviously GRUB is installed. But where exactly? /dev/sda or /dev/sda1

These guides will give you the basics of dual-booting with Windows on a UEFI system.

• Linux on UEFI: A Quick Installation Guide, by Roderick W. Smith
• [TUTORIAL] Installing Mint on a Windows 8/8.1 Computer

Is there a Install-Log where i can see this?

You can run the Boot Info Script, which will compile all that information for you.
Install boot-info-script:

Code: Select all

sudo apt-get install boot-info-script

Then run the script:

Code: Select all

sudo bootinfoscript

[srs5694]

Your specific original questions have all been answered, I believe. For further information, I recommend:

• Adam Williamson's blog entry on how EFI works -- This page describes the theory behind EFI-mode booting.
• My page on installing Linux on EFI systems -- This page is a more practical introduction to EFI-mode booting than the preceding one.
• My page on EFI boot loaders for Linux -- This page describes EFI boot loader choices for Linux systems.
• Installing Mint on a Windows 8/8.1 Computer -- This is a tutorial on this site written by gold_finger, which is Mint-specific.

[netlord]

Hi there

thank you for the hints - I´ve learned a lot and managed to install it.

However - I have one more Issue: for some Reasons I´m forced to use a specific GRUB-Version.
To be exact - this one: https://github.com/biosbits

Can someone give me a hint how to use this version?

Thanks

*edit*
At the moment I´m using the Version 2.02~beta2-9ubuntu1.3

[srs5694]

However - I have one more Issue: for some Reasons I´m forced to use a specific GRUB-Version.
To be exact - this one: https://github.com/biosbits

I'd never heard of that tool before today. A quick perusal suggests that it's intended for some very high-level and specialized functions. It's also not clear if it's a BIOS tool or an EFI tool. (Its name suggests the former, but with the rampant mis-use of the term "BIOS," I can't really be sure of that.)

In any event, for 99.99% of users, there should be no need to use that tool. If you could elaborate on why you think you need it, perhaps that would help us provide better advice. If you're a developer who really does need that boot loader, then I recommend you contact its author for any help in setting it up. It's such an exotic tool that you're unlikely to get help on it here.

[netlord]

In any event, for 99.99% of users, there should be no need to use that tool. If you could elaborate on why you think you need it, perhaps that would help us provide better advice. If you're a developer who really does need that boot loader, then I recommend you contact its author for any help in setting it up. It's such an exotic tool that you're unlikely to get help on it here.

Well, then I´m the 0.01 %

Biosbits it written by a (genius) guy called Josh Triplett and allows using of python-scripts in GRUB, before booting the OS.
Thats exact what I need here in my Company. We have to check some values in the BIOS before booting the OS (actually Win 8.1 and soon Win 10) in UEFI-Mode.

I´ve handled the installation of GRUB in the UEFI-Partition and its booting. With the 2.02 Version. But I need Josh´s Grub.

However - i cloned his Project on my laptop and will try with this version.

BTW: Regardless of my needs - the Question is how to use a specific version of a tool if it shouldn´t be the newest...

[srs5694]

There's a Python implementation for EFI, so you can run Python scripts from just about any boot manager -- you'd just need to configure the boot manager to run the Python interpreter with the right options to launch whatever Python scripts you want to run. That said, I've never done this myself, and I don't happen to have a URL handy for an EFI Python binary, so I can't be much more help on that score.

As to the question of installing some random EFI binary, perhaps this page of mine will help, at least for EFI programs. Alternatively, you could use my rEFInd boot manager: set up the program you want to run in a subdirectory of the "EFI" directory on the ESP (for instance, "EFI/myprogram/foo.efi"). rEFInd should then detect it and enable you to launch it.