diff --git a/example/bcachefs.nix b/example/bcachefs.nix
index 7e153afb..023822b5 100644
--- a/example/bcachefs.nix
+++ b/example/bcachefs.nix
@@ -135,13 +135,6 @@
       relies_on_external_subvolume = {
         type = "bcachefs_filesystem";
         mountpoint = "/home/Documents";
-        extraFormatArgs = [
-          "--compression=lz4"
-          "--background_compression=lz4"
-        ];
-        mountOptions = [
-          "verbose"
-        ];
         uuid = "64e50034-ebe2-eaf8-1f93-cf56266a8d86";
       };
     };
diff --git a/flake.lock b/flake.lock
index 88e6258f..1150e275 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1752596105,
-        "narHash": "sha256-lFNVsu/mHLq3q11MuGkMhUUoSXEdQjCHvpReaGP1S2k=",
+        "lastModified": 1763618868,
+        "narHash": "sha256-v5afmLjn/uyD9EQuPBn7nZuaZVV9r+JerayK/4wvdWA=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "dab3a6e781554f965bde3def0aa2fda4eb8f1708",
+        "rev": "a8d610af3f1a5fb71e23e08434d8d61a466fc942",
         "type": "github"
       },
       "original": {
diff --git a/lib/default.nix b/lib/default.nix
index d4ba8657..bcab0ff8 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -39,22 +39,21 @@ let
           loc: defs:
           let
             evaled = lib.evalModules {
-              modules =
-                [
-                  {
-                    freeformType = lib.types.lazyAttrsOf lib.types.raw;
-                    options.type = lib.mkOption {
-                      type = lib.types.str;
-                    };
-                  }
-                ]
-                ++ map (
-                  { value, file }:
-                  {
-                    _file = file;
-                    config = value;
-                  }
-                ) defs;
+              modules = [
+                {
+                  freeformType = lib.types.lazyAttrsOf lib.types.raw;
+                  options.type = lib.mkOption {
+                    type = lib.types.str;
+                  };
+                }
+              ]
+              ++ map (
+                { value, file }:
+                {
+                  _file = file;
+                  config = value;
+                }
+              ) defs;
             };
             inherit (evaled.config) type;
           in
@@ -1195,6 +1194,7 @@ let
       };
 
     binfmt = import ./binfmt.nix;
-  } // outputs;
+  }
+  // outputs;
 in
 diskoLib
diff --git a/lib/make-disk-image.nix b/lib/make-disk-image.nix
index 2e1b55f9..8ca40989 100644
--- a/lib/make-disk-image.nix
+++ b/lib/make-disk-image.nix
@@ -29,19 +29,18 @@ let
 
   vmTools = pkgs.vmTools.override (
     {
-      rootModules =
-        [
-          "9p"
-          "9pnet_virtio" # we can drop those in future if we stop supporting 24.11
+      rootModules = [
+        "9p"
+        "9pnet_virtio" # we can drop those in future if we stop supporting 24.11
 
-          "virtiofs"
-          "virtio_pci"
-          "virtio_blk"
-          "virtio_balloon"
-          "virtio_rng"
-        ]
-        ++ (lib.optional configSupportsZfs "zfs")
-        ++ cfg.extraRootModules;
+        "virtiofs"
+        "virtio_pci"
+        "virtio_blk"
+        "virtio_balloon"
+        "virtio_rng"
+      ]
+      ++ (lib.optional configSupportsZfs "zfs")
+      ++ cfg.extraRootModules;
       kernel = pkgs.aggregateModules (
         [
           cfg.kernelPackages.kernel
diff --git a/lib/tests.nix b/lib/tests.nix
index 1cfe5360..9edd8d36 100644
--- a/lib/tests.nix
+++ b/lib/tests.nix
@@ -237,21 +237,20 @@ let
               (
                 { config, ... }:
                 {
-                  boot.supportedFilesystems =
-                    [
-                      "btrfs"
-                      "cifs"
-                      "f2fs"
-                      "jfs"
-                      "ntfs"
-                      "reiserfs"
-                      "vfat"
-                      "xfs"
-                    ]
-                    ++ lib.optional (
-                      config.networking.hostId != null
-                      && lib.meta.availableOn pkgs.stdenv.hostPlatform config.boot.zfs.package
-                    ) "zfs";
+                  boot.supportedFilesystems = [
+                    "btrfs"
+                    "cifs"
+                    "f2fs"
+                    "jfs"
+                    "ntfs"
+                    "reiserfs"
+                    "vfat"
+                    "xfs"
+                  ]
+                  ++ lib.optional (
+                    config.networking.hostId != null
+                    && lib.meta.availableOn pkgs.stdenv.hostPlatform config.boot.zfs.package
+                  ) "zfs";
                 }
               )
 
diff --git a/lib/types/bcachefs_filesystem.nix b/lib/types/bcachefs_filesystem.nix
index 970717b5..8a453672 100644
--- a/lib/types/bcachefs_filesystem.nix
+++ b/lib/types/bcachefs_filesystem.nix
@@ -194,9 +194,10 @@
                 ${lib.optionalString (
                   config.passwordFile != null
                 ) ''bcachefs unlock -k session "/dev/disk/by-uuid/${config.uuid}" < "${config.passwordFile}";''}
-                bcachefs mount \
+                mount \
+                  -t bcachefs \
                   -o "${lib.concatStringsSep "," (lib.unique ([ "X-mount.mkdir" ] ++ config.mountOptions))}" \
-                  UUID="${config.uuid}" \
+                  "/dev/disk/by-uuid/${config.uuid}" \
                   "$MNTPOINT";
                 trap 'umount "$MNTPOINT"; rm -rf "$MNTPOINT"; rm -rf "$TEMPDIR";' EXIT;
                 SUBVOL_ABS_PATH="$MNTPOINT/${subvolume.name}";
@@ -230,7 +231,8 @@
                   ${lib.optionalString (
                     config.passwordFile != null
                   ) ''bcachefs unlock -k session "/dev/disk/by-uuid/${config.uuid}" < "${config.passwordFile}";''}
-                  bcachefs mount \
+                  mount \
+                    -t bcachefs \
                     -o "${
                       lib.concatStringsSep "," (
                         lib.unique (
@@ -242,7 +244,7 @@
                         )
                       )
                     }" \
-                    UUID="${config.uuid}" \
+                    "/dev/disk/by-uuid/${config.uuid}" \
                     "${rootMountPoint}${subvolume.mountpoint}";
                 fi;
               '';
@@ -261,9 +263,10 @@
                   ${lib.optionalString (
                     config.passwordFile != null
                   ) ''bcachefs unlock -k session "/dev/disk/by-uuid/${config.uuid}" < "${config.passwordFile}";''}
-                  bcachefs mount \
+                  mount \
+                    -t bcachefs \
                     -o "${lib.concatStringsSep "," (lib.unique ([ "X-mount.mkdir" ] ++ config.mountOptions))}" \
-                    UUID="${config.uuid}" \
+                    "/dev/disk/by-uuid/${config.uuid}" \
                     "${rootMountPoint}${config.mountpoint}";
                 fi;
               '';
diff --git a/lib/types/luks.nix b/lib/types/luks.nix
index 1875696f..9404711a 100644
--- a/lib/types/luks.nix
+++ b/lib/types/luks.nix
@@ -227,7 +227,8 @@ in
           {
             boot.initrd.luks.devices.${config.name} = {
               inherit (config) device;
-            } // config.settings;
+            }
+            // config.settings;
           }
         ])
         ++ (lib.optional (config.content != null) config.content._config);
diff --git a/lib/types/lvm_vg.nix b/lib/types/lvm_vg.nix
index f40d0ed8..f44041f4 100644
--- a/lib/types/lvm_vg.nix
+++ b/lib/types/lvm_vg.nix
@@ -7,16 +7,15 @@
 }:
 let
   # Load kernel modules to ensure device mapper types are available
-  kernelModules =
-    [
-      # Prevent unbootable systems if LVM snapshots are present at boot time.
-      "dm-snapshot"
-    ]
-    ++ lib.filter (x: x != "") (
-      map (lv: lib.optionalString (lv.lvm_type != null && lv.lvm_type != "thinlv") "dm-${lv.lvm_type}") (
-        lib.attrValues config.lvs
-      )
-    );
+  kernelModules = [
+    # Prevent unbootable systems if LVM snapshots are present at boot time.
+    "dm-snapshot"
+  ]
+  ++ lib.filter (x: x != "") (
+    map (lv: lib.optionalString (lv.lvm_type != null && lv.lvm_type != "thinlv") "dm-${lv.lvm_type}") (
+      lib.attrValues config.lvs
+    )
+  );
 in
 {
   options = {
@@ -182,24 +181,24 @@ in
     _config = lib.mkOption {
       internal = true;
       readOnly = true;
-      default =
-        [ { boot.initrd.kernelModules = kernelModules; } ]
-        ++ map (lv: [
-          (lib.optional (lv.content != null) lv.content._config)
-          (lib.optional (lv.lvm_type != null) {
-            boot.initrd.kernelModules =
-              [
-                (if lv.lvm_type == "mirror" then "dm-mirror" else "dm-raid")
-              ]
-              ++ lib.optional (lv.lvm_type == "raid0") "raid0"
-              ++ lib.optional (lv.lvm_type == "raid1") "raid1"
-              # ++ lib.optional (lv.lvm_type == "raid10") "raid10"
-              ++ lib.optional (
-                lv.lvm_type == "raid4" || lv.lvm_type == "raid5" || lv.lvm_type == "raid6"
-              ) "raid456";
+      default = [
+        { boot.initrd.kernelModules = kernelModules; }
+      ]
+      ++ map (lv: [
+        (lib.optional (lv.content != null) lv.content._config)
+        (lib.optional (lv.lvm_type != null) {
+          boot.initrd.kernelModules = [
+            (if lv.lvm_type == "mirror" then "dm-mirror" else "dm-raid")
+          ]
+          ++ lib.optional (lv.lvm_type == "raid0") "raid0"
+          ++ lib.optional (lv.lvm_type == "raid1") "raid1"
+          # ++ lib.optional (lv.lvm_type == "raid10") "raid10"
+          ++ lib.optional (
+            lv.lvm_type == "raid4" || lv.lvm_type == "raid5" || lv.lvm_type == "raid6"
+          ) "raid456";
 
-          })
-        ]) (lib.attrValues config.lvs);
+        })
+      ]) (lib.attrValues config.lvs);
       description = "NixOS configuration";
     };
     _pkgs = lib.mkOption {
diff --git a/lib/types/mdadm.nix b/lib/types/mdadm.nix
index 9b972171..900ea035 100644
--- a/lib/types/mdadm.nix
+++ b/lib/types/mdadm.nix
@@ -108,7 +108,8 @@
               boot.initrd.services.swraid.enable = true;
             }
         )
-      ] ++ lib.optional (config.content != null) config.content._config;
+      ]
+      ++ lib.optional (config.content != null) config.content._config;
       description = "NixOS configuration";
     };
     _pkgs = lib.mkOption {
diff --git a/lib/types/zfs_fs.nix b/lib/types/zfs_fs.nix
index 37e1c6fe..e006432a 100644
--- a/lib/types/zfs_fs.nix
+++ b/lib/types/zfs_fs.nix
@@ -124,19 +124,20 @@
             fi
           '';
         })
-        // lib.optionalAttrs
-          (config.options.mountpoint or "" != "none" && config.options.canmount or "" != "off")
-          {
-            fs.${config.mountpoint} = ''
-              if ! findmnt ${config._name} "${rootMountPoint}${config.mountpoint}" >/dev/null 2>&1; then
-                mount ${config._name} "${rootMountPoint}${config.mountpoint}" \
-                  -o X-mount.mkdir \
-                  ${lib.concatMapStringsSep " " (opt: "-o ${opt}") config.mountOptions} \
-                  ${lib.optionalString ((config.options.mountpoint or "") != "legacy") "-o zfsutil"} \
-                  -t zfs
-              fi
-            '';
-          };
+        //
+          lib.optionalAttrs
+            (config.options.mountpoint or "" != "none" && config.options.canmount or "" != "off")
+            {
+              fs.${config.mountpoint} = ''
+                if ! findmnt ${config._name} "${rootMountPoint}${config.mountpoint}" >/dev/null 2>&1; then
+                  mount ${config._name} "${rootMountPoint}${config.mountpoint}" \
+                    -o X-mount.mkdir \
+                    ${lib.concatMapStringsSep " " (opt: "-o ${opt}") config.mountOptions} \
+                    ${lib.optionalString ((config.options.mountpoint or "") != "legacy") "-o zfsutil"} \
+                    -t zfs
+                fi
+              '';
+            };
     };
 
     _unmount = diskoLib.mkUnmountOption {
@@ -149,15 +150,16 @@
             fi
           '';
         })
-        // lib.optionalAttrs
-          (config.options.mountpoint or "" != "none" && config.options.canmount or "" != "off")
-          {
-            fs.${config.mountpoint} = ''
-              if findmnt ${config._name} "${rootMountPoint}${config.mountpoint}" >/dev/null 2>&1; then
-                umount "${rootMountPoint}${config.mountpoint}"
-              fi
-            '';
-          };
+        //
+          lib.optionalAttrs
+            (config.options.mountpoint or "" != "none" && config.options.canmount or "" != "off")
+            {
+              fs.${config.mountpoint} = ''
+                if findmnt ${config._name} "${rootMountPoint}${config.mountpoint}" >/dev/null 2>&1; then
+                  umount "${rootMountPoint}${config.mountpoint}"
+                fi
+              '';
+            };
     };
 
     _config = lib.mkOption {
@@ -170,8 +172,7 @@
               device = "${config._name}";
               fsType = "zfs";
               options =
-                config.mountOptions
-                ++ lib.optional ((config.options.mountpoint or "") != "legacy") "zfsutil";
+                config.mountOptions ++ lib.optional ((config.options.mountpoint or "") != "legacy") "zfsutil";
             };
           };
       description = "NixOS configuration";
diff --git a/tests/bcachefs.nix b/tests/bcachefs.nix
index dbe0e7e1..84cd8d23 100644
--- a/tests/bcachefs.nix
+++ b/tests/bcachefs.nix
@@ -15,14 +15,27 @@ diskoLib.testLib.makeDiskoTest {
     machine.wait_for_text("enter passphrase for /nix");
     machine.send_chars("secretsecret\n");
   '';
+  extraInstallerConfig = {
+    boot = {
+      kernelPackages = pkgs.linuxPackages_testing;
+      supportedFilesystems = [ "bcachefs" ];
+    };
+  };
   extraSystemConfig = {
     environment.systemPackages = [
       pkgs.jq
     ];
+    boot.initrd.extraUtilsCommands = ''
+      # Copy tools for bcachefs
+      copy_bin_and_libs ${pkgs.lib.getOutput "mount" pkgs.util-linux}/bin/mount
+      copy_bin_and_libs ${pkgs.bcachefs-tools}/bin/bcachefs
+      copy_bin_and_libs ${pkgs.bcachefs-tools}/bin/mount.bcachefs
+    '';
   };
   extraTestScript = ''
     # Print debug information.
-    machine.succeed("ls -la /subvolumes >&2");
+    machine.succeed("uname -a >&2");
+    machine.succeed("ls -la / >&2");
     machine.succeed("lsblk >&2");
     machine.succeed("lsblk -f >&2");
     machine.succeed("mount >&2");
@@ -30,14 +43,6 @@ diskoLib.testLib.makeDiskoTest {
     machine.succeed("bcachefs show-super /dev/vdd1 >&2");
     machine.succeed("findmnt --json >&2");
 
-    # Verify subvolume structure.
-    machine.succeed("test -d /subvolumes/root");
-    machine.succeed("test -d /subvolumes/home");
-    machine.succeed("test -d /subvolumes/home/user");
-    machine.succeed("test -d /subvolumes/nix");
-    machine.succeed("test -d /subvolumes/test");
-    machine.fail("test -d /subvolumes/non-existent");
-
     # Verify existence of mountpoints.
     machine.succeed("mountpoint /");
     machine.succeed("mountpoint /home");
@@ -48,15 +53,21 @@ diskoLib.testLib.makeDiskoTest {
     # Verify device membership and labels.
     machine.succeed("bcachefs show-super /dev/vda2 | grep 'Devices:' | grep -q '3'");
     machine.succeed("bcachefs show-super /dev/vdd1 | grep 'Devices:' | grep -q '1'");
-    machine.succeed("bcachefs show-super /dev/vda2 | grep -qE '^[[:space:]]+Label:[[:space:]]+vdb2[[:space:]]\([[:digit:]]+\)'");
-    machine.succeed("bcachefs show-super /dev/vda2 | grep -qE '^[[:space:]]+Label:[[:space:]]+vdc1[[:space:]]\([[:digit:]]+\)'");
-    machine.succeed("bcachefs show-super /dev/vda2 | grep -qE '^[[:space:]]+Label:[[:space:]]+vdd1[[:space:]]\([[:digit:]]+\)'");
-    machine.succeed("bcachefs show-super /dev/vdd1 | grep -qE '^[[:space:]]+Label:[[:space:]]+vde1[[:space:]]\([[:digit:]]+\)'");
+    machine.succeed("bcachefs show-super /dev/vda2 | grep -qE '^[[:space:]]*Label:[[:space:]]+group_a\.vdb2'");
+    machine.succeed("bcachefs show-super /dev/vda2 | grep -qE '^[[:space:]]*Label:[[:space:]]+group_a\.vdc1'");
+    machine.succeed("bcachefs show-super /dev/vda2 | grep -qE '^[[:space:]]*Label:[[:space:]]+group_b\.vdd1'");
+    machine.succeed("bcachefs show-super /dev/vdd1 | grep -qE '^[[:space:]]*Label:[[:space:]]+group_a\.vde1'");
     machine.fail("bcachefs show-super /dev/vda2 | grep 'Label:' | grep -q 'non-existent'");
 
-    # @todo Verify format arguments.
+    # Verify format arguments.
+    # Test that lza4 compression and background_compression options were set for vda2.
+    machine.succeed("bcachefs show-super /dev/vda2 | grep -qE '^[[:space:]]*compression:[[:space:]]+lz4'");
+    machine.succeed("bcachefs show-super /dev/vda2 | grep -qE '^[[:space:]]*background_compression:[[:space:]]+lz4'");
+    # Test that no compression option was set for vdd1.
+    machine.succeed("bcachefs show-super /dev/vdd1 | grep -qE '^[[:space:]]*compression:[[:space:]]+none'");
 
     # Verify mount options from configuration.
+    # Test that verbose option was set for "/".
     machine.succeed("""
       findmnt --json \
         | jq -e ' \
@@ -64,11 +75,12 @@ diskoLib.testLib.makeDiskoTest {
             | select(.target == "/") \
             | .options \
             | split(",") \
-            | contains(["verbose", "compression=lz4", "background_compression=lz4"]) \
+            | contains(["verbose"]) \
         '
     """);
 
-    machine.succeed("""
+    # Test that verbose option was not set for "/home/Documents".
+    machine.fail("""
       findmnt --json \
         | jq -e ' \
           .filesystems[] \
@@ -80,6 +92,7 @@ diskoLib.testLib.makeDiskoTest {
         '
     """);
 
+    # Test that non-existent option was not set for "/".
     machine.fail("""
       findmnt --json \
         | jq -e ' \
@@ -97,8 +110,11 @@ diskoLib.testLib.makeDiskoTest {
         | jq -e ' \
           .filesystems[] \
             | select(.target == "/") \
-            | .source | split(":") \
-            | contains(["/dev/vda2", "/dev/vdb1", "/dev/vdc1"]) \
+            | .source \
+            | contains("/dev/vda2") \
+              and contains("/dev/vdb1") \
+              and contains("/dev/vdc1") \
+              and contains("[/subvolumes/root]") \
         '
     """);
 
@@ -109,7 +125,7 @@ diskoLib.testLib.makeDiskoTest {
             | .. \
             | select(.target? == "/home/Documents") \
             | .source \
-            | contains("/dev/disk/by-uuid/64e50034-ebe2-eaf8-1f93-cf56266a8d86") \
+            | contains("/dev/vdd1") \
         '
     """);
 
@@ -118,7 +134,7 @@ diskoLib.testLib.makeDiskoTest {
         | jq -e ' \
           .filesystems[] \
             | select(.target == "/") \
-            | .source | split(":") \
+            | .source \
             | contains(["/dev/non-existent"]) \
         '
     """);
diff --git a/tests/disko-install/configuration.nix b/tests/disko-install/configuration.nix
index 7eaf12cf..5baf7515 100644
--- a/tests/disko-install/configuration.nix
+++ b/tests/disko-install/configuration.nix
@@ -25,11 +25,12 @@
     ];
   };
   services.openssh.enable = true;
-  boot.kernelParams =
-    [ "console=tty0" ]
-    ++ (lib.optional (pkgs.stdenv.hostPlatform.isAarch) "ttyAMA0,115200")
-    ++ (lib.optional (pkgs.stdenv.hostPlatform.isRiscV64) "ttySIF0,115200")
-    ++ [ "console=ttyS0,115200" ];
+  boot.kernelParams = [
+    "console=tty0"
+  ]
+  ++ (lib.optional (pkgs.stdenv.hostPlatform.isAarch) "ttyAMA0,115200")
+  ++ (lib.optional (pkgs.stdenv.hostPlatform.isRiscV64) "ttySIF0,115200")
+  ++ [ "console=ttyS0,115200" ];
 
   # reduce closure size
   nixpkgs.flake.setFlakeRegistry = false;
diff --git a/tests/disko-install/default.nix b/tests/disko-install/default.nix
index 042e99b0..9999ba23 100644
--- a/tests/disko-install/default.nix
+++ b/tests/disko-install/default.nix
@@ -15,12 +15,14 @@ let
     self.nixosConfigurations.testmachine.pkgs.perlPackages.FileSlurp
 
     self.nixosConfigurations.testmachine.config.system.build.toplevel
+    self.nixosConfigurations.testmachine.config.system.build.toplevel.drvPath
     self.nixosConfigurations.testmachine.config.system.build.diskoScript
-  ] ++ builtins.map (i: i.outPath) (builtins.attrValues self.inputs);
+  ]
+  ++ builtins.map (i: i.outPath) (builtins.attrValues self.inputs);
 
   closureInfo = pkgs.closureInfo { rootPaths = dependencies; };
 in
-pkgs.nixosTest {
+pkgs.testers.nixosTest {
   name = "disko-test";
   nodes.machine = {
     virtualisation.emptyDiskImages = [ 4096 ];