Dual Boot PopOS

PopOS uses systemd-boot for startup instead of grub. As a result, modifying the boot menu is slightly different.

Setup multiple boot

It generally recommended to install each OS on a dedicated drive. Furthermore, when installing the OS, you can physically disconnect any extra drives to ensure that Windows, PopOS or any other OS doesn’t accidently corrupt your data/EFI partitions. This is especially recommended when dealing with Windows.

In all cases, it’s ideal to install Windows first followed by Linux distributions.

Modify boot menu

Assuming you’re using PopOS, or another OS that utilizes systemd-boot, you can add an additional OS to the boot menu as follows:

  1. Add timeout so the menu appears. Edit /boot/efi/loader/loader.conf and add the following
    timeout 5
    

    For a 5 second timeout

  2. Mount the windows (or any other OS) EFI partition. You can list the partions using sudo fdisk -l. Look for partitions of type EFI System, you should have at least 1 or more for each OS you have available.

fdisk

In this case, I want to mount the Windows EFI partition located at /dev/sda1

  1. Mount the partition to a temporary folder
mkdir /tmp/efi_partition
sudo mount /dev/sda1 /tmp/efi_partition
  1. Within this mount you will locate a folder with the name of the OS (Microsoft in this case) you need to copy this to the PopOS EFI partition
sudo cp -R /tmp/efi_partition/Microsoft /boot/efi/EFI

Now you can chose the OS to boot.

References