diff --git a/dangerzone/__init__.py b/dangerzone/__init__.py
index 1afa5d38b..1bbab6b8b 100644
--- a/dangerzone/__init__.py
+++ b/dangerzone/__init__.py
@@ -4,7 +4,7 @@
 try:
     from . import vendor  # type: ignore [attr-defined]
 
-    sys.path.insert(0, os.path.dirname(vendor.__file__))
+    sys.path.insert(0, vendor.__path__[0])
 except ImportError:
     pass
 
diff --git a/debian/rules b/debian/rules
index 1b737ae23..fbcb61178 100755
--- a/debian/rules
+++ b/debian/rules
@@ -1,13 +1,13 @@
 #!/usr/bin/make -f
 export PYBUILD_NAME=dangerzone
 export DEB_BUILD_OPTIONS=nocheck
-
-# XXX: Expanding the glob here, because the ./vendor dir does not exist yet.
-DZ_BUILD_DIR=$(wildcard $(CURDIR)/.pybuild/cpython3*/build/)
+export PYBUILD_INSTALL_ARGS=--install-lib=/usr/lib/python3/dist-packages
+export PYTHONDONTWRITEBYTECODE=1
+export DH_VERBOSE=1
 
 %:
 	dh $@ --with python3 --buildsystem=pybuild
 
 override_dh_builddeb:
-	./install/linux/vendor-pymupdf.py --dest $(DZ_BUILD_DIR)/dangerzone/vendor
+	./install/linux/vendor-pymupdf.py --dest debian/dangerzone/usr/lib/python3/dist-packages/dangerzone/vendor/
 	dh_builddeb $@