diff --git a/Cargo.toml b/Cargo.toml
index e3d0d1f..8a7cec2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -38,4 +38,4 @@ serde = ["dep:serde"]
 rlp = ["dep:alloy-rlp"]
 arbitrary = ["dep:arbitrary", "dep:proptest"]
 
-schema = ["dep:schemars"]
+schema = ["std", "dep:schemars"]
diff --git a/src/spec.rs b/src/spec.rs
index 61b3f08..b1ed73a 100644
--- a/src/spec.rs
+++ b/src/spec.rs
@@ -97,11 +97,13 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(miri, ignore = "no fs")]
     fn spec_up_to_date() {
         ensure_file_contents(Path::new(JSON_PATH), &json_chains());
     }
 
     #[test]
+    #[cfg_attr(miri, ignore = "no fs")]
     fn schema_up_to_date() {
         ensure_file_contents(Path::new(SCHEMA_PATH), &json_schema());
     }