diff --git a/spack.yaml b/spack.yaml
index ab00b83..25bd5f3 100644
--- a/spack.yaml
+++ b/spack.yaml
@@ -6,7 +6,13 @@
 # https://github.com/ACCESS-NRI/model-deployment-template/blob/main/spack.yaml
 spack:
   specs:
-    - access-om3@git.2025.08.001
+    # used to have: - access-om3@git.2025.08.001
+    # angus-g MOM6 code https://github.com/angus-g/MOM6/tree/ag-orig, i.e., `5a185920b1231849966ec35ee8f77ffe2f348d37` 
+    # =2025.07.000 means spack will use that set of dependencies to concretise
+    # see https://github.com/ACCESS-NRI/spack-packages/blob/fd44ae03141eab221ce0e5b587dbb9c81d411fcb/packages/access-mom6/package.py#L27
+    # link regarding the Debug flag https://spack-tutorial.readthedocs.io/en/latest/tutorial_buildsystems.html#cmake
+    - access-mom6@git.5a185920b1231849966ec35ee8f77ffe2f348d37=2025.07.000 fflags="-march=sapphirerapids -mtune=sapphirerapids -unroll" cflags="-march=sapphirerapids -mtune=sapphirerapids -unroll" cxxflags="-march=sapphirerapids -mtune=sapphirerapids -unroll" ~access3
+    - access-mom6@git.5a185920b1231849966ec35ee8f77ffe2f348d37=2025.07.000 fflags="-march=sapphirerapids -mtune=sapphirerapids -unroll" cflags="-march=sapphirerapids -mtune=sapphirerapids -unroll" cxxflags="-march=sapphirerapids -mtune=sapphirerapids -unroll" ~access3 build_type=Debug
   packages:
     # Main Dependencies
     access3: