diff --git a/backend.py b/backend.py
index 88862a4f..32e2efa5 100644
--- a/backend.py
+++ b/backend.py
@@ -448,7 +448,7 @@ def add_repos(main_repositories, update_repositories, repos, repo_gpgcheck, gpgc
         for device in getRemovableDeviceList():
             util.runCmd2(['eject', device])
 
-    if interactive:
+    if interactive and constants.HAS_SUPPLEMENTAL_PACKS:
         # Add supp packs in a loop
         while True:
             media_ans = dict(answers_pristine)
diff --git a/constants.py b/constants.py
index 05cf2f74..ec83e9f9 100644
--- a/constants.py
+++ b/constants.py
@@ -186,3 +186,4 @@ def error_string(error, logname, with_hd):
 FEATURES_DIR = "/etc/xensource/features"
 HAS_RAID_ASSEMBLE = os.path.exists(os.path.join(FEATURES_DIR, "raid-assemble"))
 HAS_RAID_CONFIGURE = os.path.exists(os.path.join(FEATURES_DIR, "raid-configure"))
+HAS_SUPPLEMENTAL_PACKS = os.path.exists(os.path.join(FEATURES_DIR, "supplemental-packs"))
diff --git a/doc/features.txt b/doc/features.txt
index 0e5bb7b8..d5e33a3c 100644
--- a/doc/features.txt
+++ b/doc/features.txt
@@ -21,3 +21,11 @@ Currently available feature flags are:
 
     Offer user the ability to configure a software-RAID volume as
     primary disk.
+
+  supplemental-packs
+
+    Support installation of supplemental packs after installation of
+    the main product.
+
+    This only impacts the UI, the <source> answerfile construct still
+    allows to include supplemental packs without this feature flag.