diff --git a/schemas/legacy.json b/schemas/legacy.json
index 16eab2d..b251c8a 100644
--- a/schemas/legacy.json
+++ b/schemas/legacy.json
@@ -822,7 +822,7 @@
                 "type": "number"
             },
             "PowerState": {
-                "type": "string"
+                "enum": ["On", "ChassisOn", "Always", "BiosPost"]
             },
             "Presence": {
                 "properties": {