diff --git a/debian/rules b/debian/rules
index 43778a4..3c209fc 100755
--- a/debian/rules
+++ b/debian/rules
@@ -77,6 +77,8 @@ override_dh_auto_configure: gencontrol
 override_dh_auto_test:
 
 override_dh_auto_install:
+	echo "systemdsystemunitdir=$(systemdsystemunitdir)" >> debian/substvars
+
 	dh_auto_install --max-parallel=1
 
 ifneq ($(ONLY_CLIENT), 1)
@@ -113,11 +115,6 @@ endif
 override_dh_missing:
 	dh_missing --fail-missing
 
-# Ensure substvars exists before dh_install (needed for older debhelper in Buster)
-override_dh_install:
-	echo "systemdsystemunitdir=$(systemdsystemunitdir)" >> debian/substvars
-	dh_install
-
 ifneq ($(ONLY_CLIENT), 1)
 override_dh_installsystemd:
 	dh_installsystemd -pfreeipa-server --no-enable ipa.service