diff --git a/build_configs.json b/build_configs.json
index 8977646..d39a573 100644
--- a/build_configs.json
+++ b/build_configs.json
@@ -65,7 +65,8 @@
     "firefox": {
         "c8": {
             "mock_options": {
-                "module_enable": ["nodejs:12"]
+                "module_enable": ["nodejs:12", "llvm-toolset:rhel8:8100020251114081043", "rust-toolset:rhel8:8100020251117112136"],
+                "yum_exclude": ["*21.1.8-1*", "*1.92.0-1*"]
             }
         },
         "a8": {