diff --git a/src/services/atom.ts b/src/services/atom.ts
index d382673..81fd763 100644
--- a/src/services/atom.ts
+++ b/src/services/atom.ts
@@ -129,6 +129,10 @@ export class AtomService extends Service {
         messages: [
           {
             content: tx.data.unsigned_tx_hash,
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "SHA256",
+            },
           },
         ],
       },
diff --git a/src/services/dydx.ts b/src/services/dydx.ts
index 1391b28..b71d7b6 100644
--- a/src/services/dydx.ts
+++ b/src/services/dydx.ts
@@ -137,6 +137,10 @@ export class DydxService extends Service {
         messages: [
           {
             content: tx.data.unsigned_tx_hash,
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "SHA256",
+            },
           },
         ],
       },
diff --git a/src/services/eth.ts b/src/services/eth.ts
index fbce363..0e1fee9 100644
--- a/src/services/eth.ts
+++ b/src/services/eth.ts
@@ -61,6 +61,10 @@ export class EthService extends Service {
         messages: [
           {
             content: tx.data.unsigned_tx_hash,
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "KECCAK256",
+            },
           },
         ],
       },
diff --git a/src/services/fet.ts b/src/services/fet.ts
index fb15363..b3f46ed 100644
--- a/src/services/fet.ts
+++ b/src/services/fet.ts
@@ -147,6 +147,10 @@ export class FetService extends Service {
           {
             content: tx.data.unsigned_tx_hash,
             derivationPath: [44, 118, integration.vaultId, 0, 0],
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "SHA256",
+            },
           },
         ],
         algorithm: SigningAlgorithm.MPC_ECDSA_SECP256K1,
diff --git a/src/services/inj.ts b/src/services/inj.ts
index c44d50b..3aae839 100644
--- a/src/services/inj.ts
+++ b/src/services/inj.ts
@@ -128,6 +128,10 @@ export class InjService extends Service {
         messages: [
           {
             content: tx.data.unsigned_tx_hash,
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "SHA256",
+            },
           },
         ],
       },
diff --git a/src/services/kava.ts b/src/services/kava.ts
index 9906b15..86acc24 100644
--- a/src/services/kava.ts
+++ b/src/services/kava.ts
@@ -128,6 +128,10 @@ export class KavaService extends Service {
         messages: [
           {
             content: tx.data.unsigned_tx_hash,
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "SHA256",
+            },
           },
         ],
       },
diff --git a/src/services/matic.ts b/src/services/matic.ts
index 24ffba3..b0fa20f 100644
--- a/src/services/matic.ts
+++ b/src/services/matic.ts
@@ -128,6 +128,10 @@ export class MaticService extends Service {
         messages: [
           {
             content: tx.data.unsigned_tx_hash,
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "KECCAK256",
+            },
           },
         ],
       },
diff --git a/src/services/noble.ts b/src/services/noble.ts
index f3e3e4a..cce64d1 100644
--- a/src/services/noble.ts
+++ b/src/services/noble.ts
@@ -71,6 +71,10 @@ export class NobleService extends Service {
         messages: [
           {
             content: tx.data.unsigned_tx_hash,
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "SHA256",
+            },
           },
         ],
       },
diff --git a/src/services/osmo.ts b/src/services/osmo.ts
index e7755c9..231f16c 100644
--- a/src/services/osmo.ts
+++ b/src/services/osmo.ts
@@ -129,6 +129,10 @@ export class OsmoService extends Service {
         messages: [
           {
             content: tx.data.unsigned_tx_hash,
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "SHA256",
+            },
           },
         ],
       },
diff --git a/src/services/tia.ts b/src/services/tia.ts
index 676fa78..38fc24f 100644
--- a/src/services/tia.ts
+++ b/src/services/tia.ts
@@ -128,6 +128,10 @@ export class TiaService extends Service {
         messages: [
           {
             content: tx.data.unsigned_tx_hash,
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "SHA256",
+            },
           },
         ],
       },
diff --git a/src/services/zeta.ts b/src/services/zeta.ts
index b4f62fa..747eada 100644
--- a/src/services/zeta.ts
+++ b/src/services/zeta.ts
@@ -147,6 +147,10 @@ export class ZetaService extends Service {
           {
             content: tx.data.unsigned_tx_hash,
             derivationPath: [44, 118, integration.vaultId, 0, 0],
+            preHash: {
+              content: tx.data.unsigned_tx_serialized,
+              hashAlgorithm: "SHA256",
+            },
           },
         ],
         algorithm: SigningAlgorithm.MPC_ECDSA_SECP256K1,