Arch Linux

vdraceil

Member

Registered: 2019-02-18

Posts: 9

[SOLVED] Arch+Win10 dual boot setup directly boots into Windows

Laptop:
Dell XPS 9500 FHD+ 16GB RAM 512GB

Settings that I updated in BIOS:
- SATA Operation: ACHI
- SecureBoot: Off
- FastBoot: Thorough

Settings that I updated in Windows 10 Home:
- Fast Startup (Power Options): Disabled

Relevant Partitions:
/dev/sda2 [EFI]
/dev/nvme0n1p7 [Linux FileSystem]
/dev/nvme0n1p8 [Linux Swap]

... Arch install successful / looked okay ...

Grub Install:

mount /dev/nvme0n1p7 /mnt
mount /dev/sda2 /mnt/efi

arch-chroot /mnt

pacman -S grub efibootmgr os-prober
grub-install --target=x86_64-efi --efi-directory=/efi --bootloader-id=GRUB
grub-mkconfig -o /boot/grub/grub.cfg

os-prober picked up "Windows Boot Manager" only after I installed

ntfs-3g

package

On reboot, I tested Arch & Windows via Grub and both loaded fine
Then, I removed the live USB and tried restarting (full shutdown + manual power on tried too) from Windows, it always goes into Windows without even showing the grub screen

When I insert the live USB back in, boot to Windows and restart, I can see the Grub screen now! .. without the live USB Grub doesnt show up.

BIOS Boot Order is as expected:
- GRUB
- Windows Boot Manager
- UEFI PC SN730 NVMe WDC 512GB

The same is confirmed by

efibootmgr -v

too.

/efi dir structure:

/efi
    /EFI
        /BOOT/BOOTX64.EFI
        /GRUB/grubx64.efi
        /Dell/logs
    /grub
        /locale
        x86_64-efi
    /arch/boot
        amd-ucode.img
        intel-ucode.img
        /x86_64
            initramfs-linux.img
            vmlinuz-linux
    /loader
        loader.conf
        /entries
            archiso-x86_64-linux.conf
            archiso-x86_64-speech-linux.conf

/boot dir structure:

/boot
    initramfs-linux-fallback.img
    initramfs-linux.img
    vmlinuz-linux
    /grub
        grub.cfg
        grubenv
        x86_64-efi
        /fonts
        /locale
        /themes

After reading the wiki, other articles, etc., I tried booting into the live USB and re-installing grub (after mounting partitions and chroot) again but with the `--removable` option.
However, it failed as the EFI partition had no more free space (67 MB full - dir structure above).

So, I tried to do as give in https://wiki.archlinux.org/title/GRUB#D … _boot_path (equivalent to using the `--removable` option during grub-install, right?) -

# mv /efi/EFI/grub /efi/EFI/BOOT
# mv /efi/EFI/BOOT/grubx64.efi /efi/EFI/BOOT/BOOTX64.EFI

After I did this, Grub screen didn't show up at all .. Strangely, when I booted into the live USB, I saw the Grub screen (launch to Arch, Windows, etc.) instead of the usual Arch entry options screen

I've been trying this and that for about a whole day now.
I feel I'm missing something small (some config, some CLI option, some setting, etc.), but not sure what it is.
Any help or pointers would be much appreciated.

Let me know if any more info is required (dir structure, cmd outputs, etc.)

Last edited by vdraceil (2021-05-07 07:05:10)

vdraceil

Member

Registered: 2019-02-18

Posts: 9

Re: [SOLVED] Arch+Win10 dual boot setup directly boots into Windows

I tried entering BIOS setup and manually clicking on "GRUB" (already at the top of the boot order), but it opens up Dell SupportAssit which then says "No bootable devices found"
So, grub is loading on boot, but it is just falling back to the second option "Windows Boot Manager", yeah?
Something wrong with my grub.cfg / fstab?

vdraceil

Member

Registered: 2019-02-18

Posts: 9

Re: [SOLVED] Arch+Win10 dual boot setup directly boots into Windows

(facepalm)
/dev/sda2 is EFI in the live USB
/dev/nvmen0p1 is the correct ESP in the SSD

I mounted this one, installed grub and all fell into place!