diff --git a/files/ansible-playbooks/update-indoor.yml b/files/ansible-playbooks/update-indoor.yml
index aaa8ecc..e7ff53f 100644
--- a/files/ansible-playbooks/update-indoor.yml
+++ b/files/ansible-playbooks/update-indoor.yml
@@ -1008,54 +1008,14 @@
     # <<< END ADDED >>>
 
     # --- SAFE expected target derivation (split into separate set_fact tasks) ---
-    - name: Derive expected indoor firmware from image filename (safe – base)
-      delegate_to: localhost
-      ansible.builtin.set_fact:
-        _img_base: "{{ image_filename | regex_replace('\\.bin$','') }}"
-      when: au_delay_sec is defined
 
-    - name: Derive X.Y.Z core from image filename (if any)
+    - name: Compute expected firmware core "X.Y.Z-rNNNN" from image filename (strict)
       delegate_to: localhost
       ansible.builtin.set_fact:
-        _img_ver_core: >-
+        expected_fw_core: >-
           {{
-            (_img_base is search('[0-9]+\\.[0-9]+\\.[0-9]+'))
-            | ternary(
-                (_img_base | regex_replace('.*?([0-9]+\\.[0-9]+\\.[0-9]+).*','\\1')),
-                ''
-              )
-          }}
-      when: au_delay_sec is defined
-
-    - name: Derive rev number from -rNNNN (preferred)
-      delegate_to: localhost
-      ansible.builtin.set_fact:
-        _img_rev_num: >-
-          {{
-            (_img_base is search('-r[0-9]+'))
-            | ternary(
-                (_img_base | regex_replace('.*-r([0-9]+).*','\\1')),
-                ''
-              )
-          }}
-      when: au_delay_sec is defined
-
-    - name: If no -rNNNN, try 'rev NNNN' (case-insensitive)
-      delegate_to: localhost
-      ansible.builtin.set_fact:
-        _img_rev_num: >-
-          {{
-            (_img_rev_num | length) > 0
-              | ternary(
-                  _img_rev_num,
-                  (
-                    (_img_base is search('(?i)rev[^0-9]*[0-9]+'))
-                    | ternary(
-                        (_img_base | regex_replace('.*(?i)rev[^0-9]*([0-9]+).*','\\1')),
-                        ''
-                      )
-                  )
-                )
+            image_filename
+            | regex_replace('.*?([0-9]+\.[0-9]+\.[0-9]+)-r([0-9]+).*','\1-r\2')
           }}
       when: au_delay_sec is defined