diff --git a/package.json b/package.json
index 23b90ee..ad7e3c1 100644
--- a/package.json
+++ b/package.json
@@ -74,9 +74,7 @@
     "ts-node": "^8.6.2",
     "typescript": "^3.7.5",
     "webpack": "^4.30.0",
-    "webpack-cli": "^3.3.2"
-  },
-  "optionalDependencies": {
-    "@chainsafe/eth2-spec-tests": "^0.11.1-fix"
+    "webpack-cli": "^3.3.2",
+    "@chainsafe/eth2-spec-tests": "0.12.0"
   }
 }
diff --git a/yarn.lock b/yarn.lock
index f448d3c..3d3165a 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -827,10 +827,10 @@
   dependencies:
     buffer "^5.4.3"
 
-"@chainsafe/eth2-spec-tests@^0.11.1-fix":
-  version "0.11.1-fixed"
-  resolved "https://registry.yarnpkg.com/@chainsafe/eth2-spec-tests/-/eth2-spec-tests-0.11.1-fixed.tgz#4c873a627740aa43c9dd85fbfcb90a528a7e6467"
-  integrity sha512-kjxeVrg5DJJXhrbydD+FSNdNj6Z2JIOitRUY7gnXVI9DRDEjAa59tZ9ZqFjx7M0UAOCJ9DLR6JdHAU/0nLLIZQ==
+"@chainsafe/eth2-spec-tests@0.12.0":
+  version "0.12.0"
+  resolved "https://registry.yarnpkg.com/@chainsafe/eth2-spec-tests/-/eth2-spec-tests-0.12.0.tgz#f95ffe5bc20ddaa4d2240cffe1e417877adc8055"
+  integrity sha512-EECbmI/1SdjSPUaQOkZqBOA6AfhviS7jlXVmAs3P2biJTeH2p0p31V4fZImR2NXAgGVFAP16sRx2OCwflOq0mw==
 
 "@chainsafe/lodestar-params@^0.5.0":
   version "0.5.0"