diff --git a/lib/spack/external/__init__.py b/lib/spack/external/__init__.py
index b6a35925d5c..603cb412c89 100644
--- a/lib/spack/external/__init__.py
+++ b/lib/spack/external/__init__.py
@@ -18,7 +18,7 @@
 
 * Homepage: https://pypi.python.org/pypi/archspec
 * Usage: Labeling, comparison and detection of microarchitectures
-* Version: 0.2.5-dev (commit cbb1fd5eb397a70d466e5160b393b87b0dbcc78f)
+* Version: 0.2.5-dev (commit bceb39528ac49dd0c876b2e9bf3e7482e9c2be4a)
 
 astunparse
 ----------------
diff --git a/lib/spack/external/archspec/cpu/microarchitecture.py b/lib/spack/external/archspec/cpu/microarchitecture.py
index 1ffe51d9184..3f4e30fab55 100644
--- a/lib/spack/external/archspec/cpu/microarchitecture.py
+++ b/lib/spack/external/archspec/cpu/microarchitecture.py
@@ -115,6 +115,9 @@ def __eq__(self, other):
             and self.cpu_part == other.cpu_part
         )
 
+    def __hash__(self):
+        return hash(self.name)
+
     @coerce_target_names
     def __ne__(self, other):
         return not self == other