diff --git a/share/spack/gitlab/cloud_pipelines/stacks/ml-darwin-aarch64-mps/spack.yaml b/share/spack/gitlab/cloud_pipelines/stacks/ml-darwin-aarch64-mps/spack.yaml
index efb29e8617f..3b204f3f94a 100644
--- a/share/spack/gitlab/cloud_pipelines/stacks/ml-darwin-aarch64-mps/spack.yaml
+++ b/share/spack/gitlab/cloud_pipelines/stacks/ml-darwin-aarch64-mps/spack.yaml
@@ -20,6 +20,8 @@ spack:
       variants: +mps~cuda~rocm
     mpi:
       require: openmpi
+    openblas:
+      require: ~fortran
 
   specs:
   # Hugging Face
diff --git a/var/spack/repos/builtin/packages/openblas/package.py b/var/spack/repos/builtin/packages/openblas/package.py
index a4f0e28b438..09aa6963fa3 100644
--- a/var/spack/repos/builtin/packages/openblas/package.py
+++ b/var/spack/repos/builtin/packages/openblas/package.py
@@ -53,7 +53,7 @@ class Openblas(MakefilePackage):
 
     variant(
         "fortran",
-        default="True",
+        default=True,
         when="@0.3.21:",
         description="w/o a Fortran compiler, OpenBLAS will build an f2c-converted LAPACK",
     )