meant to build an aarch64 image with the much flash-friendlier nilfs2 filesystem for root

sd-aarch64-nilfs.nix

{ nixpkgs ? <nixpkgs>, system ? "aarch64-linux" } :

let
  myisoconfig = { pkgs, config, ...}: {
    imports = [
      "${nixpkgs}/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix"
    ];

    boot = {
      kernelParams = [ "cma=32M" ];
      
      # for this and every other instance of the string 'nilfs', there may be a 2 at the end--not sure
      supportedFilesystems = [ "nilfs" ]; 
      
      # pretty sure this is how mkForce works
      postBootCommands =  pkgs.lib.mkForce ''
      # On the first boot do some maintenance tasks
      if [ -f /nix-path-registration ]; then

        # Figure out device names for the boot device and root filesystem.
        rootPart=$(readlink -f /dev/disk/by-label/NIXOS_SD)
        bootDevice=$(lsblk -npo PKNAME $rootPart)

        # I don't know how nilfs's resizing utils are meant to work; see also:
        # https://github.com/NixOS/nixpkgs/pull/42183
        # https://github.com/NixOS/nixpkgs/issues/42242
        # also, resizing to only half capacity to leave room for swap may be ideal--nilfs supports online resize anyway
        
        # Resize the root partition and the filesystem to fit the disk
        # echo ",+," | sfdisk -N2 --no-reread $bootDevice
        # ${pkgs.parted}/bin/partprobe
        # ${pkgs.e2fsprogs}/bin/resize2fs $rootPart

        # Register the contents of the initial Nix store
        ${config.nix.package.out}/bin/nix-store --load-db < /nix-path-registration

        # nixos-rebuild also requires a "system" profile and an /etc/NIXOS tag.
        touch /etc/NIXOS
        ${config.nix.package.out}/bin/nix-env -p /nix/var/nix/profiles/system --set /run/current-system

        # Prevents this from running on later boots.
        rm -f /nix-path-registration
      fi
    '';
    };
 
    environment.systemPackages = with pkgs; [ vim ];
 
    users.extraUsers.root = {
      packages = with pkgs; [ nilfs-utils lynx vim w3m ];
      initialPassword = "nixos";
    };
 
    fileSystems = {
      "/boot" = {
        # commented out because this seems to be inherited,
        # might be better of simply removed for that reason
        
        #device = "/dev/disk/by-label/NIXOS_BOOT";
        #fsType = "vfat";
      };
      "/" = {
        #device = "/dev/disk/by-label/NIXOS_SD";
        fsType = pkgs.lib.mkForce "nilfs";
      };
    };
 
  };
 
  evalNixos = configuration: import "${nixpkgs}/nixos" {
    inherit system configuration;
  };
 
in { sd = (evalNixos myisoconfig).config.system.build.sdImage; }