Dual boot (UEFI)

update-grub automatically takes care of this by probing the EFI directory.

It adds the following in /boot/grub/grub.cfg which makes it possible to load windows using Grub:

### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows Boot Manager (on /dev/nvme0n1p1)' --class windows --class os $menuentry_id_option 'osprober-efi-62F9-0A97' {
     insmod part_gpt
     insmod fat
     search --no-floppy --fs-uuid --set=root 62F9-0A97
     chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
### END /etc/grub.d/30_os-prober ###

Needless to say, EFI partition needs to exist - this can be seen in the /etc/fstab

cat /etc/fstab | grep -i efi

UUID=62F9-0A97       /efi            vfat            rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro   0 2

Reference

Arch boot process: https://wiki.archlinux.org/title/Arch_boot_process

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• Tags: linux windows grub