diff --git a/ognibuild/debian/fix_build.py b/ognibuild/debian/fix_build.py
index 4abf1c5..6dc7eb0 100644
--- a/ognibuild/debian/fix_build.py
+++ b/ognibuild/debian/fix_build.py
@@ -22,6 +22,7 @@ __all__ = [
 from datetime import datetime
 import logging
 import os
+import shutil
 import sys
 from typing import List, Set, Optional, Type, Tuple
 
@@ -543,7 +544,9 @@ class PgBuildExtOutOfDateControlFixer(BuildFixer):
     def _fix(self, error, context):
         logging.info("Running 'pg_buildext updatecontrol'")
         self.session.check_call(["pg_buildext", "updatecontrol"])
-        # TODO(jelmer): Copy control file back
+        shutil.copy(
+            self.session.external_path('debian/control'),
+            context.tree.abspath(os.path.join(context.subpath, 'debian/control')))
         return commit_debian_changes(
             context.tree,
             context.subpath,
@@ -744,6 +747,8 @@ def main(argv=None):
 
     args = parser.parse_args()
     from breezy.workingtree import WorkingTree
+    import breezy.git
+    import breezy.bzr
     from .apt import AptManager
     from ..session.plain import PlainSession
     from ..session.schroot import SchrootSession
diff --git a/ognibuild/session/__init__.py b/ognibuild/session/__init__.py
index 0908903..f9f0225 100644
--- a/ognibuild/session/__init__.py
+++ b/ognibuild/session/__init__.py
@@ -97,6 +97,9 @@ class Session(object):
     def setup_from_directory(self, path, subdir="package") -> Tuple[str, str]:
         raise NotImplementedError(self.setup_from_directory)
 
+    def external_path(self, path: str) -> str:
+        raise NotImplementedError
+
 
 class SessionSetupFailure(Exception):
     """Session failed to be set up."""
diff --git a/ognibuild/session/plain.py b/ognibuild/session/plain.py
index bec2ae8..a27631e 100644
--- a/ognibuild/session/plain.py
+++ b/ognibuild/session/plain.py
@@ -92,6 +92,9 @@ class PlainSession(Session):
     def chdir(self, path):
         os.chdir(path)
 
+    def external_path(self, path):
+        return os.path.abspath(path)
+
     def setup_from_vcs(
             self, tree, include_controldir=None, subdir="package"):
         from ..vcs import dupe_vcs_tree, export_vcs_tree
diff --git a/ognibuild/session/schroot.py b/ognibuild/session/schroot.py
index 4026669..2faeeb6 100644
--- a/ognibuild/session/schroot.py
+++ b/ognibuild/session/schroot.py
@@ -177,17 +177,17 @@ class SchrootSession(Session):
         self.check_call(["mkdir", "-p", home], cwd="/", user="root")
         self.check_call(["chown", user, home], cwd="/", user="root")
 
-    def _fullpath(self, path: str) -> str:
+    def external_path(self, path: str) -> str:
         if self._cwd is None:
             raise ValueError("no cwd set")
         return os.path.join(self.location, os.path.join(self._cwd, path).lstrip("/"))
 
     def exists(self, path: str) -> bool:
-        fullpath = self._fullpath(path)
+        fullpath = self.external_path(path)
         return os.path.exists(fullpath)
 
     def scandir(self, path: str):
-        fullpath = self._fullpath(path)
+        fullpath = self.external_path(path)
         return os.scandir(fullpath)
 
     def setup_from_vcs(