disko-install error "'/boot' is not a mounted partition"

[nothingnesses]

Hello. I've been trying to use disko-install to install NixOS on to my system, but I'm running into an error. Here is my set up:

/tmp/install/disko/disko-install/configuration.nix

{ config, lib, pkgs, ... }:
{
  imports =
    [
      ./hardware-configuration.nix
    ];
  boot.loader.systemd-boot.enable = true;
  boot.loader.efi.canTouchEfiVariables = true;
  networking.wireless.iwd.enable = true;
  time.timeZone = "Europe/London";
  i18n.defaultLocale = "en_GB.UTF-8";
  console = {
    keyMap = "uk";
  };
  services.xserver.enable = false;
  services.xserver.xkb.layout = "gb";
  services.pipewire = {
    enable = true;
    pulse.enable = true;
  };
  users.users.a = {
    isNormalUser = true;
    extraGroups = [ "wheel" ];
    packages = with pkgs; [
    ];
  };
  environment.systemPackages = with pkgs; [
  ];
  system.stateVersion = "24.11";
}

/tmp/install/disko/disko-install/flake.nix

{
  inputs.nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
  inputs.disko.url = "github:nix-community/disko/latest";
  inputs.disko.inputs.nixpkgs.follows = "nixpkgs";
  outputs = { self, disko, nixpkgs }: {
    nixosConfigurations.mymachine = nixpkgs.legacyPackages.x86_64-linux.nixos [
      ./configuration.nix
      disko.nixosModules.disko
      {
        disko.devices = {
          disk = {
            main = {
              type = "disk";
              device = "/dev/nvme0n1";
              content = {
                type = "gpt";
                partitions = {
                  ESP = {
                    size = "8G";
                    type = "EF00";
                    content = {
                      type = "filesystem";
                      format = "vfat";
                      mountpoint = "/boot";
                      mountOptions = [ "umask=0077" ];
                    };
                  };
                  root = {
                    size = "100%";
                    content = {
                      type = "luks";
                      name = "crypted";
                      passwordFile = "/tmp/secret.key";
                      settings = {
                        allowDiscards = true;
                      };
                      content = {
                        type = "filesystem";
                        format = "bcachefs";
                        mountpoint = "/";
                      };
                    };
                  };
                };
              };
            };
          };
        };
      }
    ];
  };
}

/tmp/install/disko/disko-install/install.sh

#!/bin/sh
source="/tmp/install/disko/disko-install";
destination="/tmp/config/etc/nixos";
echo -n 'password' > /tmp/secret.key;
nixos-generate-config --root /tmp/config --no-filesystems;
cp -f "${source}/configuration.nix" "${destination}/";
cp -f "${source}/flake.nix" "${destination}/";
sudo script -c "nix --extra-experimental-features 'nix-command flakes' run 'github:nix-community/disko/latest#disko-install' -- --write-efi-boot-entries --flake '${destination}#mymachine' --disk main /dev/nvme0n1" "${source}/log";

To start the installation, first I run a live NixOS environment from a Ventoy flash drive on the system. Then I mount another flash drive containing the above files at mountpoint "/tmp/install/". Then I run the shell script above with sh /tmp/install/disko/disko-install/install.sh. These are the outputs:

/tmp/install/disko/disko-install/log (truncated)

...
depmod: WARNING: could not open modules.builtin.modinfo at /nix/store/wz1r9l458bj8apf0vsbybkb4mgjpwpbr-linux-6.13.3-modules-shrunk/lib/modules/6.13.3: No such file or directory
building '/nix/store/2fmcnjdylkk6wf32x5kqvkk2qgfz9jxi-initrd-linux-6.13.3.drv'...
building '/nix/store/xwhcl77c1hxh0q9ardd5mbin40pdn66h-boot.json.drv'...
building '/nix/store/s72wk2a56akg38qmyy4s7mm8kfhi72kh-nixos-system-nixos-25.05pre-git.drv'...
building '/nix/store/cbmgn6mbz44n8xr6ryvqgy8p8qbq988n-closure-info.drv'...
structuredAttrs is enabled
umount: /mnt/disko-install-root: not mounted
++ realpath /dev/nvme0n1
+ disk=/dev/nvme0n1
+ lsblk -a -f
NAME        FSTYPE      FSVER            LABEL                      UUID                                 FSAVAIL FSUSE% MOUNTPOINTS
loop0       squashfs    4.0                                                                                    0   100% /nix/.ro-store
loop1                                                                                                                   
loop2                                                                                                                   
loop3                                                                                                                   
loop4                                                                                                                   
loop5                                                                                                                   
loop6                                                                                                                   
loop7                                                                                                                   
sda                                                                                                                     
├─sda1      exfat       1.0              Ventoy                     4E21-0000                                           
│ ├─ventoy  iso9660     Joliet Extension nixos-minimal-24.11-x86_64 1980-01-01-00-00-00-00                     0   100% /iso
│ └─sda1    exfat       1.0              Ventoy                     4E21-0000                                           
└─sda2      vfat        FAT16            VTOYEFI                    2205-E719                                           
sdb                                                                                                                     
└─sdb1      vfat        FAT32                                       2459-9AAA                              14.6G     0% /tmp/install
nvme0n1                                                                                                                 
├─nvme0n1p1                                                                                                             
├─nvme0n1p2 vfat        FAT32                                       1FCB-69A0                                           
└─nvme0n1p3 crypto_LUKS 2                                           f040e70d-1437-4335-8028-2932c5e7f9a8                
+ lsblk --output-all --json
+ bash -x
++ dirname /nix/store/3ys93zsghig63qpcs67vc37x0rwn1zhl-disk-deactivate/disk-deactivate
+ jq -r --arg disk_to_clear /dev/nvme0n1 -f /nix/store/3ys93zsghig63qpcs67vc37x0rwn1zhl-disk-deactivate/disk-deactivate.jq
+ set -fu
++ type zdb
++ zdb -l /dev/nvme0n1p1
++ sed -nr 's/ +name: '\''(.*)'\''/\1/p'
+ zpool=
+ [[ -n '' ]]
+ unset zpool
+ wipefs --all -f /dev/nvme0n1p1
+ wipefs --all -f /dev/nvme0n1p2
/dev/nvme0n1p2: 8 bytes were erased at offset 0x00000052 (vfat): 46 41 54 33 32 20 20 20
/dev/nvme0n1p2: 1 byte was erased at offset 0x00000000 (vfat): eb
/dev/nvme0n1p2: 2 bytes were erased at offset 0x000001fe (vfat): 55 aa
+ wipefs --all -f /dev/nvme0n1p3
/dev/nvme0n1p3: 6 bytes were erased at offset 0x00000000 (crypto_LUKS): 4c 55 4b 53 ba be
/dev/nvme0n1p3: 6 bytes were erased at offset 0x00004000 (crypto_LUKS): 53 4b 55 4c ba be
++ type zdb
++ zdb -l /dev/nvme0n1
++ sed -nr 's/ +name: '\''(.*)'\''/\1/p'
+ zpool=
+ [[ -n '' ]]
+ unset zpool
++ lsblk /dev/nvme0n1 -l -p -o type,name
++ awk 'match($1,"raid.*") {print $2}'
+ md_dev=
+ [[ -n '' ]]
+ wipefs --all -f /dev/nvme0n1
/dev/nvme0n1: 8 bytes were erased at offset 0x00000200 (gpt): 45 46 49 20 50 41 52 54
/dev/nvme0n1: 8 bytes were erased at offset 0x1d1c1115e00 (gpt): 45 46 49 20 50 41 52 54
/dev/nvme0n1: 2 bytes were erased at offset 0x000001fe (PMBR): 55 aa
+ dd if=/dev/zero of=/dev/nvme0n1 bs=440 count=1
1+0 records in
1+0 records out
440 bytes copied, 0.000202269 s, 2.2 MB/s
+ lsblk -a -f
NAME       FSTYPE   FSVER            LABEL                      UUID                                 FSAVAIL FSUSE% MOUNTPOINTS
loop0      squashfs 4.0                                                                                    0   100% /nix/.ro-store
loop1                                                                                                               
loop2                                                                                                               
loop3                                                                                                               
loop4                                                                                                               
loop5                                                                                                               
loop6                                                                                                               
loop7                                                                                                               
sda                                                                                                                 
├─sda1     exfat    1.0              Ventoy                     4E21-0000                                           
│ ├─ventoy iso9660  Joliet Extension nixos-minimal-24.11-x86_64 1980-01-01-00-00-00-00                     0   100% /iso
│ └─sda1   exfat    1.0              Ventoy                     4E21-0000                                           
└─sda2     vfat     FAT16            VTOYEFI                    2205-E719                                           
sdb                                                                                                                 
└─sdb1     vfat     FAT32                                       2459-9AAA                              14.6G     0% /tmp/install
nvme0n1                                                                                                             
++ mktemp -d
+ disko_devices_dir=/tmp/tmp.bgbtesscLi
+ trap 'rm -rf "$disko_devices_dir"' EXIT
+ mkdir -p /tmp/tmp.bgbtesscLi
+ device=/dev/nvme0n1
+ imageName=main
+ imageSize=2G
+ name=main
+ type=disk
+ device=/dev/nvme0n1
+ efiGptPartitionFirst=1
+ type=gpt
+ blkid /dev/nvme0n1
+ sgdisk --clear /dev/nvme0n1
Creating new GPT entries in memory.
The operation has completed successfully.
+ sgdisk --align-end --new=1:0:+8G --change-name=1:disk-main-ESP --typecode=1:EF00 /dev/nvme0n1
The operation has completed successfully.
+ partprobe /dev/nvme0n1
+ udevadm trigger --subsystem-match=block
+ udevadm settle
+ sgdisk --align-end --new=2:0:-0 --change-name=2:disk-main-root --typecode=2:8300 /dev/nvme0n1
The operation has completed successfully.
+ partprobe /dev/nvme0n1
+ udevadm trigger --subsystem-match=block
+ udevadm settle
+ device=/dev/disk/by-partlabel/disk-main-ESP
+ extraArgs=()
+ declare -a extraArgs
+ format=vfat
+ mountOptions=('umask=0077')
+ declare -a mountOptions
+ mountpoint=/boot
+ type=filesystem
+ blkid /dev/disk/by-partlabel/disk-main-ESP
+ grep -q TYPE=
+ mkfs.vfat /dev/disk/by-partlabel/disk-main-ESP
mkfs.fat 4.2 (2021-01-31)
+ additionalKeyFiles=()
+ declare -a additionalKeyFiles
+ askPassword=
+ device=/dev/disk/by-partlabel/disk-main-root
+ extraFormatArgs=()
+ declare -a extraFormatArgs
+ extraOpenArgs=()
+ declare -a extraOpenArgs
+ initrdUnlock=1
+ keyFile=
+ name=crypted
+ passwordFile=/tmp/secret.key
+ settings=(['allowDiscards']='1')
+ declare -A settings
+ type=luks
+ blkid /dev/disk/by-partlabel/disk-main-root
+ blkid /dev/disk/by-partlabel/disk-main-root -o export
+ grep -q '^TYPE='
+ cryptsetup -q luksFormat /dev/disk/by-partlabel/disk-main-root --key-file /dev/fd/63
++ set +x
+ cryptsetup open /dev/disk/by-partlabel/disk-main-root crypted --allow-discards --key-file /dev/fd/63 --persistent
++ set +x
+ device=/dev/mapper/crypted
+ extraArgs=()
+ declare -a extraArgs
+ format=bcachefs
+ mountOptions=('defaults')
+ declare -a mountOptions
+ mountpoint=/
+ type=filesystem
+ blkid /dev/mapper/crypted
+ grep -q TYPE=
+ mkfs.bcachefs /dev/mapper/crypted
Refusing to format when using libblkid 2.39.4
libblkid >= 2.40.1 is required to check for existing filesystems
Earlier versions may not recognize some bcachefs filesystems.

+ rm -rf /tmp/tmp.bgbtesscLi
Copying store paths
Loading nix database
installing the boot loader...
setting up /etc...
efiSysMountPoint = '/boot' is not a mounted partition. Is the path configured correctly?
Traceback (most recent call last):
  File "/nix/store/7vkvjqgs6rzh2g80lcn3wn5qim286bfc-systemd-boot/bin/systemd-boot", line 431, in <module>
    main()
  File "/nix/store/7vkvjqgs6rzh2g80lcn3wn5qim286bfc-systemd-boot/bin/systemd-boot", line 411, in main
    run([CHECK_MOUNTPOINTS])
  File "/nix/store/7vkvjqgs6rzh2g80lcn3wn5qim286bfc-systemd-boot/bin/systemd-boot", line 58, in run
    return subprocess.run(cmd, check=True, text=True, stdout=stdout)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/0l539chjmcq5kdd43j6dgdjky4sjl7hl-python3-3.12.8/lib/python3.12/subprocess.py", line 571, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['/nix/store/jpd5q73wqvbiq39yihp35m1aklp85a47-check-mountpoints']' returned non-zero exit status 1.
Failed to install bootloader
disko-install failed
rmdir: failed to remove '/mnt/disko-install-root': Directory not empty

Script done on 2025-02-23 09:29:23+00:00 [COMMAND_EXIT_CODE="1"]

This is the full log file.

I'm not sure what disko-install is supposed to do exactly, but I'm assuming it's supposed to mount the partitions it creates to mountpoints in "/mnt/disko-install-root/" (so it can later use something like chroot/proot to use that as "/" and proceed with the rest of the installation), which it didn't seem like it did (since there's the line saying "umount: /mnt/disko-install-root: not mounted").

Please can you tell me what I'm doing wrong and what I should do to make the installation proceed?