diff --git a/subiquity/common/filesystem/manipulator.py b/subiquity/common/filesystem/manipulator.py
index a92ebf86..3fba58f9 100644
--- a/subiquity/common/filesystem/manipulator.py
+++ b/subiquity/common/filesystem/manipulator.py
@@ -75,6 +75,16 @@ def scale_partitions(all_factors, disk_size):
     return ret
 
 
+def get_efi_size(disk):
+    all_factors = (uefi_scale, bootfs_scale, rootfs_scale)
+    return scale_partitions(all_factors, disk.size)[0]
+
+
+def get_bootfs_size(disk):
+    all_factors = (uefi_scale, bootfs_scale, rootfs_scale)
+    return scale_partitions(all_factors, disk.size)[1]
+
+
 class FilesystemManipulator:
 
     def create_mount(self, fs, spec):
@@ -138,14 +148,6 @@ class FilesystemManipulator:
         self.clear(part)
         self.model.remove_partition(part)
 
-    def _get_efi_size(self, disk):
-        all_factors = (uefi_scale, bootfs_scale, rootfs_scale)
-        return scale_partitions(all_factors, disk.size)[0]
-
-    def _get_bootfs_size(self, disk):
-        all_factors = (uefi_scale, bootfs_scale, rootfs_scale)
-        return scale_partitions(all_factors, disk.size)[1]
-
     def _create_boot_with_resize(self, disk, spec, **kwargs):
         part_size = spec['size']
         if part_size > gaps.largest_gap_size(disk):
@@ -156,7 +158,7 @@ class FilesystemManipulator:
     def _create_boot_partition(self, disk):
         bootloader = self.model.bootloader
         if bootloader == Bootloader.UEFI:
-            part_size = self._get_efi_size(disk)
+            part_size = get_efi_size(disk)
             log.debug('_create_boot_partition - adding EFI partition')
             spec = dict(size=part_size, fstype='fat32')
             if self.model._mount_for_path("/boot/efi") is None:
diff --git a/subiquity/common/filesystem/tests/test_manipulator.py b/subiquity/common/filesystem/tests/test_manipulator.py
index aea116a7..9e980b9c 100644
--- a/subiquity/common/filesystem/tests/test_manipulator.py
+++ b/subiquity/common/filesystem/tests/test_manipulator.py
@@ -22,6 +22,8 @@ from subiquity.common.filesystem import gaps
 from subiquity.common.filesystem.manipulator import (
     bootfs_scale,
     FilesystemManipulator,
+    get_efi_size,
+    get_bootfs_size,
     PartitionScaleFactors,
     scale_partitions,
     uefi_scale,
@@ -271,15 +273,15 @@ class TestPartitionSizeScaling(unittest.TestCase):
         ]
         for disk_size, uefi, bootfs in tests:
             disk = make_disk(manipulator.model, preserve=True, size=disk_size)
-            self.assertEqual(uefi, manipulator._get_efi_size(disk))
-            self.assertEqual(bootfs, manipulator._get_bootfs_size(disk))
+            self.assertEqual(uefi, get_efi_size(disk))
+            self.assertEqual(bootfs, get_bootfs_size(disk))
 
         # something in between for scaling
         disk_size = 15 << 30
         disk = make_disk(manipulator.model, preserve=True, size=disk_size)
-        efi_size = manipulator._get_efi_size(disk)
+        efi_size = get_efi_size(disk)
         self.assertTrue(uefi_scale.maximum > efi_size)
         self.assertTrue(efi_size > uefi_scale.minimum)
-        bootfs_size = manipulator._get_bootfs_size(disk)
+        bootfs_size = get_bootfs_size(disk)
         self.assertTrue(bootfs_scale.maximum > bootfs_size)
         self.assertTrue(bootfs_size > bootfs_scale.minimum)
diff --git a/subiquity/server/controllers/filesystem.py b/subiquity/server/controllers/filesystem.py
index 3b1259f8..c57f1b02 100644
--- a/subiquity/server/controllers/filesystem.py
+++ b/subiquity/server/controllers/filesystem.py
@@ -41,7 +41,10 @@ from subiquity.common.filesystem.actions import (
     DeviceAction,
     )
 from subiquity.common.filesystem import boot, gaps, labels
-from subiquity.common.filesystem.manipulator import FilesystemManipulator
+from subiquity.common.filesystem.manipulator import (
+    FilesystemManipulator,
+    get_bootfs_size,
+)
 from subiquity.common.types import (
     Bootloader,
     Disk,
@@ -140,7 +143,7 @@ class FilesystemController(SubiquityController, FilesystemManipulator):
             self.add_boot_disk(disk)
         self.create_partition(
             device=disk, spec=dict(
-                size=self._get_bootfs_size(disk),
+                size=get_bootfs_size(disk),
                 fstype="ext4",
                 mount='/boot'
                 ))