I have upgraded my four (4) main phones to android 15, and installed magisk, lsposed framework, and BCR, to ensure my normal required functionality is present.

NixOS Impermanence Setup

Boot machine with Nixos installer usb. Close installer, open terminal, open firefox at

https://github.com/vimjoyer/impermanent-setup

Become su by running sudo su

add tree to the shell with

nix-shell -p tree

use lsblk to determine disk to install to.

In this case identifies sda

Download the disko configuration

curl https://raw.githubusercontent.com/vimjoyer/impermanent-setup/main/final/disko.nix -o /tmp/disko.nix

replace "/dev/vda" with "/dev/sda"

Partition the drives using disko.nix flake

sudo nix --experimental-features "nix-command flakes" run github:nix-community/disko -- --mode disko /tmp/disko.nix --arg device '"/dev/sda"'

Use lsblk to check partitions. We should have these sub volumes mounted at /mnt - check with tree /mnt tree /tmp

/mnt
├──boot
├──nix
└──persist

/tmp
├──disko.nix

Configuration

Generate with sudo nixos-generate-config --no-filesystems --root /mnt

/mnt
├──boot
├──etc
│  └──nixos
│    ├──configuration.nix
│    └──hardware-configuration.nix
├──nix
└──persist

/tmp
├──disko.nix

Move disko.nix into the config files directory with mv /tmp/disko.nix /mnt/etc/nixos/

/mnt
├──boot
├──etc
│  └──nixos
│    ├──configuration.nix
│    ├──disko.nix
│    └──hardware-configuration.nix
├──nix
└──persist

Initialise flake using

nix --extra-experimental-features "nix-command flakes" flake init --template github:vimjoyer/impermanent-setup

# flake.nix
{
  description = "Nixos config flake";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";

    disko = {
      url = "github:nix-community/disko";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # impermanence = {
    #   url = "github:nix-community/impermanence";
    # };

    # home-manager = {
    #   url = "github:nix-community/home-manager";
    #   inputs.nixpkgs.follows = "nixpkgs";
    # };
  };

  outputs = {nixpkgs, ...} @ inputs:
  {
    nixosConfigurations.default = nixpkgs.lib.nixosSystem {
      specialArgs = {inherit inputs;};
      modules = [
        inputs.disko.nixosModules.default
        (import ./disko.nix { device = "/dev/vda"; })

        ./configuration.nix

        # inputs.home-manager.nixosModules.default
        # inputs.impermanence.nixosModules.impermanence
      ];
    };
  };
}

Move the flake.nix to the configuration directory with mv flake.nix /mnt/etc/nixos/

/mnt
├──boot
├──etc
│  └──nixos
│     ├──configuration.nix
│     ├──disko.nix
│     ├──flake.nix
│     └──hardware-configuration.nix
├──nix
└──persist

Edit nano /mnt/etc/nixos/flake.nix to replace (import ./disko.nix { device = "/dev/vda"; }) with (import ./disko.nix { device = "/dev/sda"; }) to provide the correct disk target

Edit nano /mnt/etc/nixos/configuration.nix comment out the service.xserver declarations, to remove a window manager

# services.xserver.enable = true;
# services.xserver.displayManager.gdm.enable = true;
# services.xserver.desktopManager.gnome.enable = true;

add a user declaration

    users.users.computer_user = {
    isNormalUser = true;
    initialPassword = "password";
    extraGroups = [ "wheel" ]; # Enable ‘sudo’ for the user.
  };

add btrfs volume management

  boot.initrd.postDeviceCommands = lib.mkAfter ''
    mkdir /btrfs_tmp
    mount /dev/root_vg/root /btrfs_tmp
    if [[ -e /btrfs_tmp/root ]]; then
        mkdir -p /btrfs_tmp/old_roots
        timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/root)" "+%Y-%m-%-d_%H:%M:%S")
        mv /btrfs_tmp/root "/btrfs_tmp/old_roots/$timestamp"
    fi

    delete_subvolume_recursively() {
        IFS=$'\n'
        for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
            delete_subvolume_recursively "/btrfs_tmp/$i"
        done
        btrfs subvolume delete "$1"
    }

    for i in $(find /btrfs_tmp/old_roots/ -maxdepth 1 -mtime +30); do
        delete_subvolume_recursively "$i"
    done

    btrfs subvolume create /btrfs_tmp/root
    umount /btrfs_tmp
  '';

Enable persistence

cp -r /mnt/etc/nixos /mnt/persist
cp -r /mnt/etc/nixos /mnt/etc/persist

/mnt
├──boot
├──etc
│  ├──nixos
│  │  ├──configuration.nix
│  │  ├──disko.nix
│  │  ├──flake.nix
│  │  └──hardware-configuration.nix
│  └──persist
│     ├──configuration.nix
│     ├──disko.nix
│     ├──flake.nix
│     └──hardware-configuration.nix
├──nix
└──persist
   └──nixos
      ├──configuration.nix
      ├──disko.nix
      ├──flake.nix
      └──hardware-configuration.nix

Install nixos from the flake config.

nixos-install --root /mnt --flake /mnt/etc/nixos#default

On Completion

You will be requested to provide a root password, and confirm it. If that is successful then

reboot

Add impermanence

Edit the flake.nix to uncomment the impermanence settings

{
  description = "Nixos config flake";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";

    disko = {
      url = "github:nix-community/disko";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    impermanence = {
      url = "github:nix-community/impermanence";
    };
.
.
.
.
.
        ./configuration.nix

        # inputs.home-manager.nixosModules.default
        inputs.impermanence.nixosModules.impermanence
      ];

Edit the configuration.nix to add the necessary impermanence settings

  fileSystems."/persist".neededForBoot = true;
  environment.persistence."/persist/system" = {
    hideMounts = true;
    directories = [
      "/etc/nixos"
      "/var/log"
      # "/var/lib/bluetooth"
      "/var/lib/nixos"
      "/var/lib/systemd/coredump"
      # "/etc/NetworkManager/system-connections"
      { directory = "/var/lib/colord"; user = "colord"; group = "colord"; mode = "u=rwx,g=rx,o="; }
    ];
    files = [
      "/etc/machine-id"
      { file = "/var/keys/secret_file"; parentDirectory = { mode = "u=rwx,g=,o="; }; }
    ];
  };

rebuild

sudo nixos-rebuild boot --flake /persist/nixos#default

sudo reboot

sudo mkdir -p /etc/
sudo cp -r /persist/nixos /etc
sudo reboot

check with tree /persist

Configure home manager to handle user environments

Sounds to me like they just want permission to go in with any weak excuse.