diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index dc0529a..7180c17 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -217,7 +217,7 @@ jobs:
         ./gradlew build
         
   build-cosmopolitan:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     timeout-minutes: 10
 
     steps: