GRUB Configuration for Dual-Boot Arch Linux and Windows 10

This guide explains how to edit and configure GRUB on Arch Linux for a dual-boot setup with Windows 10, ensuring the GRUB menu displays correctly for selecting Arch Linux or Windows.

Prerequisites

Arch Linux and Windows 10 installed on a UEFI system.
GRUB bootloader installed (sudo pacman -S grub).
os-prober installed to detect Windows (sudo pacman -S os-prober).

Step-by-Step Instructions

1. Edit GRUB Configuration

The main GRUB configuration file is /etc/default/grub. Edit it to customize boot behavior.

Open the Configuration File:

   sudo nano /etc/default/grub

Key Settings to Modify:
- Timeout and Menu Display:
```
 GRUB_TIMEOUT=5
 GRUB_TIMEOUT_STYLE=menu
```

 - `GRUB_TIMEOUT=5`: Shows GRUB menu for 5 seconds.
 - `GRUB_TIMEOUT_STYLE=menu`: Ensures the menu is visible.

Kernel Parameters:
```
 GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3"
```
- loglevel=3: Reduces boot verbosity but keeps essential messages.
Graphical Resolution:
```
 GRUB_GFXMODE=auto
 GRUB_GFXPAYLOAD_LINUX=keep
```
- GRUB_GFXMODE=auto: Sets GRUB resolution automatically.
- GRUB_GFXPAYLOAD_LINUX=keep: Maintains graphical mode for the kernel.
Windows Detection:
```
 GRUB_DISABLE_OS_PROBER=false
```
- Ensures os-prober detects Windows Boot Manager.
Optional GRUB Theme (for a custom GRUB menu look):
```
 GRUB_THEME="/usr/share/grub/themes/Vimix/theme.txt"
```
- Install a theme: yay -S grub-theme-vimix.

Save Changes:
- In nano, press Ctrl+O, Enter, then Ctrl+X to save and exit.

2. Update GRUB Configuration

Regenerate the GRUB configuration to apply changes:

sudo grub-mkconfig -o /boot/grub/grub.cfg

This detects Arch Linux (/boot/vmlinuz-linux, /boot/initramfs-linux.img) and Windows Boot Manager (e.g., on /dev/nvme0n1p2@/efi/Microsoft/Boot/bootmgfw.efi).

3. (Optional) Reinstall GRUB

If GRUB isn’t displaying or booting correctly:

sudo grub-install
sudo grub-mkconfig -o /boot/grub/grub.cfg

Ensure your EFI partition is mounted at /boot/efi before running grub-install.

4. Reboot

Reboot to apply changes:

reboot

You should see the GRUB menu with entries for Arch Linux, Windows Boot Manager, and a UEFI Firmware Settings option.

5. Troubleshooting

Backup Configuration:

  sudo cp /etc/default/grub /etc/default/grub.bak

Check GRUB Output: Run sudo grub-mkconfig -o /boot/grub/grub.cfg and verify it detects both Arch Linux and Windows.
Manually Edit at Boot: Press e at the GRUB menu to temporarily edit boot parameters.
Check Logs:

  journalctl -b

Look for errors related to GRUB.

Verify UEFI Mode:

  ls /sys/firmware/efi

If the directory exists, you’re in UEFI mode.

Notes

Your system uses /boot/intel-ucode.img for Intel microcode updates, which is correctly detected.
Ensure os-prober is installed to detect Windows Boot Manager.
If the GRUB menu doesn’t display, check your Dell laptop’s BIOS/UEFI settings to ensure UEFI boot is enabled and Secure Boot is disabled if needed.
For GPU issues (e.g., display glitches), install appropriate drivers:

  sudo pacman -S nvidia nvidia-utils  # For NVIDIA
  sudo pacman -S mesa xf86-video-amdgpu  # For AMD
  sudo pacman -S mesa xf86-video-intel  # For Intel

Ashen Chathuranga @ktauchathuranga