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**jlittle** · Jul 30, 2020, 07:42 PM

Originally posted by Nimic View Post

To be clear im using the asrock mobo uefi the windows bios is legacy. And i have a seperate partition for the kubuntu efi. Not sure if that makes a difference.

It certainly does. If the computer is in EFI, it cannot run BIOS programmes, like the Windows bootloader; the BIOS is not there; and vice versa.

You could reinstall Kubuntu as BIOS/MBR, or even conceivably BIOS/GPT, then grub will be able to chain to the Windows bootloader. Or, reinstall Windows as using EFI; supposedly one could convert Windows in place to EFI, but I've no idea if that's a good idea.

If you want to do a BIOS install of Kubuntu, you have to boot the install media in BIOS mode. How to achieve that depends on the motherboard.

**Nimic** · Jul 31, 2020, 05:08 AM

Actually windows is on a GPT drive not mbr.
How can I confirm kubuntu is running in efi mode?

**Nimic** · Jul 31, 2020, 05:30 AM

Is there any advantage to running in uefi mode. It would take about the same effort to put windows in uefi mode. (I already have fast boot and secure boot disabled)

**oshunluvr** · Jul 31, 2020, 07:40 AM

Originally posted by Nimic View Post

Is there any advantage to running in uefi mode. It would take about the same effort to put windows in uefi mode. (I already have fast boot and secure boot disabled)

Frankly, I didn't know one could run Windows 10 in non-uefi mode. A couple of points need to be made here:
GRUB will boot either to EFI or Legacy.
If GRUB is on an MBR drive, it should "just work."
If GRUB is on a GPT drive, which I recommend, you need to prepare a small BIOS_BOOT partition, of which I have written about extensively elsewhere on this forum.

I'm not even close to an expert on EFI, but if your Windows install is booting to legacy mode, I'm of the "it's Windows so leave it alone" camp. What I find curious is; if you are indeed in legacy mode and Windows is not using EFI, why did GRUB choose to install in EFI mode? That's seems abnormal to me. IME, GRUB (or more properly the installation tool) detects the EFI partition and will then install in EFI mode. If it's not there, then it installs in legacy mode.

Finally, it also seems possible that one could boot to a Live USB and install GRUB is legacy mode from the live session and avoid an entire re-install, but I've never tried it. It might actually be less work to just re-install Linux but I'd re-partition the drive first and remove any EFI partitions first if they're not being used.

**oshunluvr** · Jul 31, 2020, 07:40 AM

Originally posted by Nimic View Post

Actually windows is on a GPT drive not mbr.
How can I confirm kubuntu is running in efi mode?

Look for the EFI partition on the Windows drive.

Here's what I think is possible: Windows is, in fact, using EFI. When you installed Linux, it detected EFI mode but didn't use the existing EFI partition because it was on another drive and thus created it's own new EFI partition on drive 2. This probably could have been avoided by choosing "Manual" partitioning at installation time and choosing the EFI partition. Now GRUB doesn't "see" the Windows install because it's only capable of using one EFI partition.

If this is the case, I think you could simply copy the Linux EFI folder(s) onto the Windows EFI partition (following the properly directory structure of course), edit /etc/fstab and change the UUID to point at the Windows EFI partition and mount it, re-install GRUB using this command:

sudo grub-install --target=x86_64-efi --efi-directory=<your windows EFI mount here> --bootloader-id=GRUB

and it should work. Running sudo update-grub after should then detect your Windows EFI bootloader and you'd be good to go. HOWEVER, I have not tried this so I cannot reliably predict the results.

Another, much more safe option, would be to simply create a custom boot stanza in /etc/grub.d/40_custom which would then allow you to boot Windows without changing anything else.

As an example, here my EFI Windows grub.cfg entry:

Code:

[FONT=monospace][COLOR=#000000]menuentry 'Windows Boot Manager (on /dev/nvme0n1p1)' --class windows --class os $menuentry_id_option 'osprober-efi-4E6E-42EE' {[/COLOR]
        insmod part_gpt
        insmod fat
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root  4E6E-42EE
        else
          search --no-floppy --fs-uuid --set=root 4E6E-42EE
        fi
        chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}

[/FONT]

Obviously, you would need to change the UUIDs to match your Windows file system.

**claydoh** · Jul 31, 2020, 08:28 AM

Originally posted by Nimic View Post

How can I confirm kubuntu is running in efi mode?

There are two ways, one is to try running the efibootmgr command, it will giver an error if it is not an EFI system. The command won't exist on a bios system, I think, so not having it may be enough to tell.
Another is to see if there is an efi directory in /sys/firmware/. It won't exist on a Bios system.

**Nimic** · Jul 31, 2020, 02:55 PM

Thanks that was helpful. I can say with certainty kubuntu is in efi mode.

As for windows. I do not have any efi partitions. I have the main partion with the full os and a recovery partition. I cant find any efi files in windows. Under sys info it says bios mode: legacy. So im pretty certain windows is in legacy mode.

In my kubuntu os partition i have some efi files with locations like: /media/(linux username)/ (win os ssd)/windows/boot/efi/bg-BG. which i believe means that kubuntu is linked to windows through a non existent efi path.

I did manually partition when i installed kubuntu. I had 1tb unallocated free space on a hdd. the other 2tb on the same hdd is ntfs format with my windows user files. I made 3 partitions of the free space: ext4 / (linux os), linux swap, ext4 /home. Then i got an error message saying i needed to make an efi partition. So i made that as fat32 /boot/efi. What im understanding it this last step where i went wrong. Should i have ignored the error and just used my three partitions.

**claydoh** · Jul 31, 2020, 03:29 PM

run the command sudo update-grub and post the output, it should look similar to this:

Code:

dohbuoy@dohbuoy-FLEX-15IIL:~$ sudo update-grub
[sudo] password for dohbuoy: 
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/99_breeze-grub.cfg'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found theme: /boot/grub/themes/breeze/theme.txt
Found linux image: /boot/vmlinuz-5.4.0-42-generic
Found initrd image: /boot/initrd.img-5.4.0-42-generic
Found linux image: /boot/vmlinuz-5.4.0-40-generic
Found initrd image: /boot/initrd.img-5.4.0-40-generic
[B]Found Windows Boot Manager on /dev/sda1@/efi/Microsoft/Boot/bootmgfw.efi[/B]
Adding boot menu entry for UEFI Firmware Settings
done

Looking to see if there are any error messages.
Above, my system is picking up the EFI partition on my Windows drive. I have one of these on each of my two drives, as I only had one when I installed Linux to the nvme drive, then I later used the recovery disk to reinstall the OEM WIndows 10 to the secondary SSD.

**Nimic** · Jul 31, 2020, 03:30 PM

I just found in "kde partition manager" i can see properties for the Microsoft reserved partition(recovery). It displays flags for "bios-grub" and "boot"
Im not sure what that means exactly but it didnt show up in the windows properties tab.

**Nimic** · Jul 31, 2020, 03:45 PM

hk-47@HK-47:~$ sudo update-grub
[sudo] password for hk-47:
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.4.0-42-generic
Found initrd image: /boot/initrd.img-5.4.0-42-generic
Found linux image: /boot/vmlinuz-5.4.0-26-generic
Found initrd image: /boot/initrd.img-5.4.0-26-generic
Adding boot menu entry for UEFI Firmware Settings
done

IF I'm reading this right grub is working fine except it isn't detecting anything windows

**Nimic** · Jul 31, 2020, 04:03 PM

Originally posted by oshunluvr View Post

Frankly, I didn't know one could run Windows 10 in non-uefi mode. A couple of points need to be made here:
GRUB will boot either to EFI or Legacy.
If GRUB is on an MBR drive, it should "just work."
If GRUB is on a GPT drive, which I recommend, you need to prepare a small BIOS_BOOT partition, of which I have written about extensively elsewhere on this forum.

I'm not even close to an expert on EFI, but if your Windows install is booting to legacy mode, I'm of the "it's Windows so leave it alone" camp. What I find curious is; if you are indeed in legacy mode and Windows is not using EFI, why did GRUB choose to install in EFI mode? That's seems abnormal to me. IME, GRUB (or more properly the installation tool) detects the EFI partition and will then install in EFI mode. If it's not there, then it installs in legacy mode.

Finally, it also seems possible that one could boot to a Live USB and install GRUB is legacy mode from the live session and avoid an entire re-install, but I've never tried it. It might actually be less work to just re-install Linux but I'd re-partition the drive first and remove any EFI partitions first if they're not being used.

Can you please post a link to what you've written on this. Even if it doesn't help my current issue it sounds interesting and is obviously a gap in my knowledge.
When I made the boot-able usb in ruffus I selected "mbr" '"legacy bios or uefi" maybe it got confused when it detected a GTP drive so it defaulted to uefi. The other option to choose would have been "GTP" "EFI (non CMS)"

**jlittle** · Jul 31, 2020, 09:54 PM

Originally posted by oshunluvr View Post

Frankly, I didn't know one could run Windows 10 in non-uefi mode.

If the Windows 10 install was upgraded all the way from a version that was a BIOS/MBR, it remains so.

**jlittle** · Jul 31, 2020, 10:12 PM

Originally posted by Nimic View Post

Thanks that was helpful. I can say with certainty kubuntu is in efi mode...
So im pretty certain windows is in legacy mode.

IMO the easiest way forward for you is to reinstall Kubuntu in legacy mode. At least, for me it would be, I'd be scared to reinstall Windows, I'd expect gotchas or licence trouble. Windows users used to say regular reinstalls were a good thing; but I haven't heard that for a while.

On my desktop with a Gigabyte motherboard, if I reboot with install USB stick plugged in and press the right key, something like F2 or F8, the firmware gives several choices referring to the stick, at least one of which is EFI mode and at least one is legacy, though how many choices and their cryptic names seem to vary from boot to boot.

**Nimic** · Jul 31, 2020, 10:40 PM

SOLVED
Thanks to eveyone that helped. I really appriciate it. I learned allot from all of your troubleshooting approches.
Turns out it was entirely user error.
First i upgraded the windows bios to uefi. (Not sure if i had to but id thought i was running uefi to begin with). Somehow windows was running legacy bios on a gtp drive. So this solution sorted that issue.
Second i reinstalled kubuntu from a usb formatted as "GTP uefi mode". I previously uses "mbr legacy bios or efi mode." I think kubuntu install saw the gtp drive and defaulted to efi mode.
Third was the user error: originally i created a new partition for linux uefi. This time i used the new windows efi partition. Low and behold grub worked without a hitch.

I used this video to convert windows to uefi mode. It was actually really easy. https://youtu.be/sT6YEOgGuBc

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Windows 10 not showing up in grub

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