diff --git a/plonky2x/core/Cargo.toml b/plonky2x/core/Cargo.toml
index 62db2dd4..83a52bcc 100644
--- a/plonky2x/core/Cargo.toml
+++ b/plonky2x/core/Cargo.toml
@@ -29,7 +29,7 @@ digest = "0.10.7"
 dotenv = "0.15.0"
 ed25519-dalek = { version = "2.0.0", features = ["rand_core"] }
 env_logger = "0.10.0"
-ethers = { version = "2.0" }
+ethers = "2.0.10"
 ff = { package = "ff", version = "0.13", features = ["derive"] }
 futures = "0.3.28"
 hex = "0.4.3"
diff --git a/plonky2x/core/src/frontend/eth/mpt/builder.rs b/plonky2x/core/src/frontend/eth/mpt/builder.rs
index 523613d3..5356e133 100644
--- a/plonky2x/core/src/frontend/eth/mpt/builder.rs
+++ b/plonky2x/core/src/frontend/eth/mpt/builder.rs
@@ -256,8 +256,13 @@ mod tests {
         );
         let circuit = builder.mock_build();
 
+        let mut key_bytes = vec![];
+        key.to_big_endian(&mut key_bytes);
+
+        let key_bytes: [u8; 32] = key_bytes.try_into().unwrap();
+
         let mut input = circuit.input();
-        input.write::<Bytes32Variable>(key);
+        input.write::<Bytes32Variable>(key_bytes.into());
         input.write::<ArrayVariable<ArrayVariable<ByteVariable, ENCODING_LEN>, PROOF_LEN>>(
             proof_as_fixed,
         );
diff --git a/plonky2x/core/src/frontend/eth/mpt/reference.rs b/plonky2x/core/src/frontend/eth/mpt/reference.rs
index a489a6c1..60a6b8eb 100644
--- a/plonky2x/core/src/frontend/eth/mpt/reference.rs
+++ b/plonky2x/core/src/frontend/eth/mpt/reference.rs
@@ -158,7 +158,13 @@ mod tests {
             .iter()
             .map(|b| b.to_vec())
             .collect::<Vec<Vec<u8>>>();
-        let storage_key = keccak256(storage_result.storage_proof[0].key.as_bytes());
+
+        let mut key_bytes = vec![];
+        storage_result.storage_proof[0]
+            .key
+            .to_big_endian(&mut key_bytes);
+
+        let storage_key = keccak256(key_bytes);
         let mut value = get(
             storage_key.into(),
             proof,