diff --git a/files/ansible-playbooks/update-indoor.yml b/files/ansible-playbooks/update-indoor.yml
index e7ff53f..c27b2fe 100644
--- a/files/ansible-playbooks/update-indoor.yml
+++ b/files/ansible-playbooks/update-indoor.yml
@@ -1019,17 +1019,15 @@
           }}
       when: au_delay_sec is defined
 
-    - name: Assemble expected_fw_core (prefer X.Y.Z-rNNNN → X.Y.Z → image base)
+    - name: Ensure expected_fw_core is set (strict parse from filename)
       delegate_to: localhost
       ansible.builtin.set_fact:
         expected_fw_core: >-
           {{
-            (_img_ver_core | length) > 0 and (_img_rev_num | length) > 0
-              and (_img_ver_core ~ '-r' ~ _img_rev_num)
-            or
-            ((_img_ver_core | length) > 0 and _img_ver_core)
-            or
-            _img_base
+            expected_fw_core | default(
+              image_filename
+              | regex_replace('.*?([0-9]+\\.[0-9]+\\.[0-9]+)-r([0-9]+).*','\\1-r\\2')
+            )
           }}
       when: au_delay_sec is defined