Dual-booting windows and nixos problems

Help
1

I am trying to dual boot Windows 10 and NixOS,
managed to install both systems on different partitions of the same drive, (NixOS graphical install)

i have a configuration from my older NixOS system + Flake, which i changed to use the GRUB bootloader (i will mention that this is my first time setting it up).

at first both systems worked fine, but now, issuing sudo nixos-rebuild switch --flake /etc/nixos/#myNixos (my flake) gives me the (shortened) error:

updating GRUB 2 menu...
installing the GRUB 2 boot loader into /boot...
Installing for x86_64-efi platform.
/nix/store/qlh04m1a1i5ix9v98nqfqmvgrwvj6y40-grub-2.12/sbin/grub-install: error: /boot doesn't look like an EFI partition.
/nix/store/pa2pnwnzkz4figsji4wnmgad9m7fa0r6-install-grub.pl: installation of GRUB EFI into /boot failed: Inappropriate ioctl for device
Failed to install bootloader
warning: error(s) occurred while switching to the new configuration

**some context of my system:**

>> lsblk --fs
NAME        FSTYPE FSVER LABEL       UUID                                 FSAVAIL FSUSE% MOUNTPOINTS
sda                                                                                      
└─sda1      ext4   1.0               05c4c68c-77c8-4591-828d-ec9199bee8f5    1,7T     2% /media/HDD
sdb                                                                                      
sdc                                                                                      
└─sdc1      vfat   FAT32 NIXOS-PLASM 1A17-076C                                           
sdd                                                                                      
nvme0n1                                                                                  
├─nvme0n1p1 ntfs                     E23EC7703EC73C73                                    
├─nvme0n1p2 ntfs                     94943A7D943A6242                                    
└─nvme0n1p3 ext4   1.0   NIXOS       691df4d9-d26c-433c-a597-aded6b1e12e8  353,2G    15% /nix/store
                                                                                         /
nvme1n1                                                                                  
└─nvme1n1p1 ext4   1.0   FREESSD     81163b6b-1264-4744-8539-221fb6f62f15  692,8G    21% /media/SSD0

grub config in configuration.nix:

  boot.loader = {
    grub = {
      enable                = true;
      fsIdentifier          = "label";
      efiSupport            = true;
      efiInstallAsRemovable = true;
      devices               = [ "nodev" ];
    };
  };

hardware-configuration.nix:

{ config, lib, pkgs, modulesPath, ... }:

{
  imports =
    [ (modulesPath + "/installer/scan/not-detected.nix")
    ];

  boot.initrd.availableKernelModules = [ "nvme" "xhci_pci" "ahci" "usbhid" "usb_storage" "sd_mod" ];
  boot.initrd.kernelModules = [ ];
  boot.kernelModules = [ "kvm-amd" ];
  boot.extraModulePackages = [ ];

  fileSystems."/" =
    { device = "/dev/disk/by-uuid/691df4d9-d26c-433c-a597-aded6b1e12e8";
      fsType = "ext4";
    };

  fileSystems."/media/HDD" =
    { device = "/dev/disk/by-uuid/05c4c68c-77c8-4591-828d-ec9199bee8f5";
      fsType = "ext4";
    };

  fileSystems."/media/SSD0" =
    { device = "/dev/disk/by-uuid/81163b6b-1264-4744-8539-221fb6f62f15";
      fsType = "ext4";
    };

  swapDevices = [ ];

  networking.useDHCP = lib.mkDefault true;


  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
  hardware.cpu.amd.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
2

view from gparted of the drive with both windows and nixos

image
image899×502 32.3 KB

3

its because the efi parition is ntfs, while linux expects a efi paritition to be fat32, wierd that windows is using ntfs for efi

4

I don’t see any efi partition, unless I’m missing something? I only see the ext4 partition marked bootable, implying MBR or that it’s an ESP iirc, and EFI-MBR is sometimes possible but a relatively niche setup IMO.

@S3NP41-v Did you check if you’re using EFI or not? The error you’re getting seems to imply… not.

5

i checked my BIOS, and indeed you are right, i had all set to legacy for whatever reason…

i take it that i will have to reinstall both of the systems to get it to work properly now?
Thank you for your help.

6

No, just change your grub configuration to disable EFI settings and point at the correct device (use by-uuid or by-label, not /dev/sda1-type identifiers!)

EDIT: I meant by-id, disks don’t have UUIDs.

7

Though, I generally recommend EFI rather than legacy BIOS, and switching at this point would uh… certainly be a little involved. But Windows has a bad habit of messing with the boot loader when you don’t use EFI.

1 Like
8

this is a fresh install of both systems, i don’t mind at all reinstalling them both to have a cleaner overall configuration

9

Yea, that seems like a good idea then. Enable EFI, and install NixOS before Windows, not the other way around, so they share the ESP and systemd-boot can automatically find Windows.

1 Like
10

If you do that wont windows make its own esp

11

No, Windows tries to reuse an existing ESP if one exists. Like, on my system, I installed Windows to a different drive entirely, and it still installed its boot loader on the ESP of my NixOS drive.

12

this was the solution,
Thank you to everyone who replied,
i didnt expect i had it all in legacy mode

also to add for someone coming after me; nixos-install adds/fixes the linux EFI entry, might help booting into the installer