diff --git a/lib/spack/llnl/util/cpu/microarchitectures.json b/lib/spack/llnl/util/cpu/microarchitectures.json
index 55b40d65ae2ac24bf6ceade9a604a68f92081f64..56f1f19df8c0077c613b02a90e4109a9102c3894 100644
--- a/lib/spack/llnl/util/cpu/microarchitectures.json
+++ b/lib/spack/llnl/util/cpu/microarchitectures.json
@@ -1214,11 +1214,11 @@
           },
           {
             "versions": "7:7.9",
-            "flags": "-march=armv8.2a+crc+crypto+fp16"
+            "flags": "-march=armv8.2-a+crc+crypto+fp16"
           },
           {
             "versions": "8:",
-            "flags": "-march=armv8.2a+crc+aes+sha2+fp16+sve -msve-vector-bits=512"
+            "flags": "-march=armv8.2-a+crc+aes+sha2+fp16+sve -msve-vector-bits=512"
           }
         ],
         "clang": [