diff --git a/crates/primitives/src/transaction/mod.rs b/crates/primitives/src/transaction/mod.rs
index 76d9b0197..f401b0ef6 100644
--- a/crates/primitives/src/transaction/mod.rs
+++ b/crates/primitives/src/transaction/mod.rs
@@ -32,7 +32,7 @@ pub use sidecar::generate_blob_sidecar;
 #[cfg(feature = "c-kzg")]
 pub use sidecar::{BlobTransaction, BlobTransactionSidecar, BlobTransactionValidationError};
 
-pub use signature::Signature;
+pub use signature::{extract_chain_id, Signature};
 pub use tx_type::{
     TxType, EIP1559_TX_TYPE_ID, EIP2930_TX_TYPE_ID, EIP4844_TX_TYPE_ID, LEGACY_TX_TYPE_ID,
 };
@@ -1740,18 +1740,9 @@ impl TryFrom<reth_rpc_types::Transaction> for TransactionSignedEcRecovered {
                         // If the transaction type is Legacy, adjust the v component of the
                         // signature according to the Ethereum specification
                         TxType::Legacy => {
-                            // Calculate the new v value based on the EIP-155 formula:
-                            // v = {0,1} + CHAIN_ID * 2 + 35
-                            !(signature.v -
-                                U256::from(if let Some(chain_id) = transaction.chain_id() {
-                                    // If CHAIN_ID is available, calculate the new v value
-                                    // accordingly
-                                    chain_id.saturating_mul(2).saturating_add(35)
-                                } else {
-                                    // If CHAIN_ID is not available, set v = {0,1} + 27
-                                    27
-                                }))
-                            .is_zero()
+                            extract_chain_id(signature.v.to())
+                                .map_err(|_| ConversionError::InvalidSignature)?
+                                .0
                         }
                         _ => !signature.v.is_zero(),
                     }
diff --git a/crates/primitives/src/transaction/signature.rs b/crates/primitives/src/transaction/signature.rs
index 8cd57dc7f..29db729e9 100644
--- a/crates/primitives/src/transaction/signature.rs
+++ b/crates/primitives/src/transaction/signature.rs
@@ -114,16 +114,11 @@ impl Signature {
                 if v == 0 && r.is_zero() && s.is_zero() {
                     return Ok((Self { r, s, odd_y_parity: false }, None))
                 }
-                return Err(RlpError::Custom("invalid Ethereum signature (V is not 27 or 28)"))
             }
-            let odd_y_parity = v == 28;
-            Ok((Self { r, s, odd_y_parity }, None))
-        } else {
-            // EIP-155: v = {0, 1} + CHAIN_ID * 2 + 35
-            let odd_y_parity = ((v - 35) % 2) != 0;
-            let chain_id = (v - 35) >> 1;
-            Ok((Self { r, s, odd_y_parity }, Some(chain_id)))
         }
+
+        let (odd_y_parity, chain_id) = extract_chain_id(v)?;
+        Ok((Self { r, s, odd_y_parity }, chain_id))
     }
 
     /// Output the length of the signature without the length of the RLP header
@@ -201,6 +196,24 @@ impl Signature {
     }
 }
 
+/// Outputs (odd_y_parity, chain_id) from the `v` value.
+/// This doesn't check validity of the `v` value for optimism.
+#[inline]
+pub fn extract_chain_id(v: u64) -> alloy_rlp::Result<(bool, Option<u64>)> {
+    if v < 35 {
+        // non-EIP-155 legacy scheme, v = 27 for even y-parity, v = 28 for odd y-parity
+        if v != 27 && v != 28 {
+            return Err(RlpError::Custom("invalid Ethereum signature (V is not 27 or 28)"))
+        }
+        Ok((v == 28, None))
+    } else {
+        // EIP-155: v = {0, 1} + CHAIN_ID * 2 + 35
+        let odd_y_parity = ((v - 35) % 2) != 0;
+        let chain_id = (v - 35) >> 1;
+        Ok((odd_y_parity, Some(chain_id)))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::{transaction::signature::SECP256K1N_HALF, Address, Signature, B256, U256};