diff --git a/crates/eth1wrap/Cargo.toml b/crates/eth1wrap/Cargo.toml
index 93ab42e9..18237e97 100644
--- a/crates/eth1wrap/Cargo.toml
+++ b/crates/eth1wrap/Cargo.toml
@@ -13,7 +13,7 @@ thiserror.workspace = true
 tokio.workspace = true
 
 [dev-dependencies]
-tokio.workspace = true
+tokio = { workspace = true, features = ["test-util"] }
 
 [lints]
 workspace = true
diff --git a/crates/eth1wrap/src/lib.rs b/crates/eth1wrap/src/lib.rs
index b8022ad6..88a859e3 100644
--- a/crates/eth1wrap/src/lib.rs
+++ b/crates/eth1wrap/src/lib.rs
@@ -20,6 +20,9 @@ sol!(
 /// indefinitely. `tokio::time::timeout` wraps the whole retried operation here.
 const ERC1271_CALL_TIMEOUT_SECS: u64 = 10;
 
+/// Magic value defined in [ERC-1271](https://eips.ethereum.org/EIPS/eip-1271).
+const MAGIC_VALUE: [u8; 4] = [0x16, 0x26, 0xba, 0x7e];
+
 type Result<T> = std::result::Result<T, EthClientError>;
 
 /// Defines errors that can occur when interacting with the Ethereum client.
@@ -96,13 +99,16 @@ impl EthClient {
         hash: [u8; 32],
         sig: &[u8],
     ) -> Result<bool> {
-        // Magic value defined in [ERC-1271](https://eips.ethereum.org/EIPS/eip-1271).
-        const MAGIC_VALUE: [u8; 4] = [0x16, 0x26, 0xba, 0x7e];
         let EthClient::Connected(provider) = self else {
             return Err(EthClientError::NoExecutionEngineAddr);
         };
 
-        let address = alloy::primitives::Address::parse_checksummed(contract_address, None)?;
+        // Any casing is accepted (no EIP-55 check), non-hex or wrong-length input
+        // is rejected rather than silently zero-padded/truncated.
+        let address = contract_address
+            .as_ref()
+            .parse::<alloy::primitives::Address>()
+            .map_err(alloy::primitives::AddressError::from)?;
 
         let instance = IERC1271::new(address, provider);
 
@@ -121,8 +127,30 @@ impl EthClient {
 
 #[cfg(test)]
 mod tests {
+    use alloy::{primitives::Bytes, providers::mock::Asserter};
+
     use super::*;
 
+    const ADDRESS: &str = "0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed";
+
+    /// ABI-encodes a `bytes4` return value as its 32-byte word.
+    fn erc1271_return(value: [u8; 4]) -> Bytes {
+        let mut word = [0u8; 32];
+        word[..4].copy_from_slice(&value);
+        Bytes::copy_from_slice(&word)
+    }
+
+    fn mocked_client(asserter: &Asserter) -> EthClient {
+        let provider = ProviderBuilder::new().connect_mocked_client(asserter.clone());
+        EthClient::Connected(provider.erased())
+    }
+
+    async fn verify(client: &EthClient, contract_address: &str) -> Result<bool> {
+        client
+            .verify_smart_contract_based_signature(contract_address, [7u8; 32], &[1, 2, 3])
+            .await
+    }
+
     #[tokio::test]
     async fn empty_address_returns_noop_client() {
         let client = EthClient::new("").await.expect("noop eth client");
@@ -137,4 +165,86 @@ mod tests {
 
         assert!(matches!(err, EthClientError::NoExecutionEngineAddr));
     }
+
+    #[tokio::test]
+    async fn any_casing_address_reaches_erc1271_call() {
+        // Lowercase, checksummed and wrong-checksum forms of the same address.
+        for address in [
+            "0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed",
+            "0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed",
+            "0x5AAeb6053F3E94C9b9A09f33669435E7Ef1BeAed",
+        ] {
+            let asserter = Asserter::new();
+            asserter.push_success(&erc1271_return(MAGIC_VALUE));
+
+            let valid = verify(&mocked_client(&asserter), address)
+                .await
+                .expect("address must parse regardless of casing");
+
+            assert!(valid);
+        }
+    }
+
+    #[tokio::test]
+    async fn malformed_address_errors() {
+        let client = mocked_client(&Asserter::new());
+
+        for address in ["not-an-address", "0x123"] {
+            let err = verify(&client, address)
+                .await
+                .expect_err("malformed address must not verify");
+
+            assert!(matches!(err, EthClientError::InvalidAddress(_)));
+        }
+    }
+
+    #[tokio::test]
+    async fn non_magic_return_is_invalid() {
+        for value in [[0u8; 4], [0xff; 4]] {
+            let asserter = Asserter::new();
+            asserter.push_success(&erc1271_return(value));
+
+            let valid = verify(&mocked_client(&asserter), ADDRESS)
+                .await
+                .expect("call must succeed");
+
+            assert!(!valid);
+        }
+    }
+
+    #[tokio::test(start_paused = true)]
+    async fn hanging_erc1271_call_times_out() {
+        // A server that accepts but never responds; paused time auto-advances
+        // to the call deadline, so the test never actually waits it out.
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0")
+            .await
+            .expect("bind local listener");
+        let endpoint = format!("http://{}", listener.local_addr().expect("local addr"));
+
+        tokio::spawn(async move {
+            let mut sockets = Vec::new();
+            while let Ok((socket, _)) = listener.accept().await {
+                // Hold sockets open; dropping them fails the request fast
+                // with a transport error instead of hanging.
+                sockets.push(socket);
+            }
+        });
+
+        let client = EthClient::new(&endpoint).await.expect("eth client");
+        let err = verify(&client, ADDRESS)
+            .await
+            .expect_err("hanging endpoint must time out");
+
+        assert!(matches!(err, EthClientError::CallTimeout));
+    }
+
+    #[tokio::test]
+    async fn non_empty_endpoint_returns_connected_client() {
+        // HTTP transports connect lazily, so nothing needs to listen here.
+        let client = EthClient::new("http://127.0.0.1:1")
+            .await
+            .expect("eth client");
+
+        assert!(matches!(client, EthClient::Connected(_)));
+    }
 }