diff --git a/target_chains/starknet/contracts/src/byte_array.cairo b/target_chains/starknet/contracts/src/byte_array.cairo
index 38e28322a5..241145fd75 100644
--- a/target_chains/starknet/contracts/src/byte_array.cairo
+++ b/target_chains/starknet/contracts/src/byte_array.cairo
@@ -10,7 +10,7 @@ pub struct ByteArray {
     num_last_bytes: u8,
     // Bytes in big endian. Each item except the last one stores 31 bytes.
     // If `num_last_bytes < 31`, unused most significant bytes of the last item will be unused.
-    data: Array<bytes31>,
+    data: Array<felt252>,
 }
 
 impl DebugByteArray of Debug<ByteArray> {
@@ -19,10 +19,7 @@ impl DebugByteArray of Debug<ByteArray> {
         let mut data = self.data.clone();
         loop {
             match data.pop_front() {
-                Option::Some(v) => {
-                    let v: u256 = v.into();
-                    write!(f, "{:?}, ", v).unwrap();
-                },
+                Option::Some(v) => { write!(f, "{:?}, ", v).unwrap(); },
                 Option::None => { break; },
             }
         };
@@ -33,7 +30,7 @@ impl DebugByteArray of Debug<ByteArray> {
 #[generate_trait]
 pub impl ByteArrayImpl of ByteArrayTrait {
     /// Creates a byte array with the data.
-    fn new(data: Array<bytes31>, num_last_bytes: u8) -> ByteArray {
+    fn new(data: Array<felt252>, num_last_bytes: u8) -> ByteArray {
         if data.len() == 0 {
             assert!(num_last_bytes == 0);
         } else {
@@ -50,7 +47,7 @@ pub impl ByteArrayImpl of ByteArrayTrait {
 
     /// Removes 31 or less bytes from the start of the array.
     /// Returns the value and the number of bytes.
-    fn pop_front(ref self: ByteArray) -> Option<(bytes31, u8)> {
+    fn pop_front(ref self: ByteArray) -> Option<(felt252, u8)> {
         let item = self.data.pop_front()?;
         if self.data.is_empty() {
             let num_bytes = self.num_last_bytes;
@@ -84,18 +81,18 @@ mod tests {
 
     #[test]
     fn byte_array_3_zeros() {
-        let mut array = ByteArrayImpl::new(array_try_into(array![0]), 3);
+        let mut array = ByteArrayImpl::new(array![0], 3);
         assert!(array.len() == 3);
-        assert!(array.pop_front() == Option::Some((0.try_into().unwrap(), 3)));
+        assert!(array.pop_front() == Option::Some((0, 3)));
         assert!(array.len() == 0);
         assert!(array.pop_front() == Option::None);
     }
 
     #[test]
     fn byte_array_3_bytes() {
-        let mut array = ByteArrayImpl::new(array_try_into(array![0x010203]), 3);
+        let mut array = ByteArrayImpl::new(array![0x010203], 3);
         assert!(array.len() == 3);
-        assert!(array.pop_front() == Option::Some((0x010203.try_into().unwrap(), 3)));
+        assert!(array.pop_front() == Option::Some((0x010203, 3)));
         assert!(array.len() == 0);
         assert!(array.pop_front() == Option::None);
     }
@@ -103,9 +100,9 @@ mod tests {
     #[test]
     fn byte_array_single_full() {
         let value_31_bytes = 0x0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f;
-        let mut array = ByteArrayImpl::new(array_try_into(array![value_31_bytes]), 31);
+        let mut array = ByteArrayImpl::new(array![value_31_bytes], 31);
         assert!(array.len() == 31);
-        assert!(array.pop_front() == Option::Some((value_31_bytes.try_into().unwrap(), 31)));
+        assert!(array.pop_front() == Option::Some((value_31_bytes, 31)));
         assert!(array.len() == 0);
         assert!(array.pop_front() == Option::None);
     }
@@ -114,13 +111,11 @@ mod tests {
     fn byte_array_two_full() {
         let value_31_bytes = 0x0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f;
         let value2_31_bytes = 0x2122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f;
-        let mut array = ByteArrayImpl::new(
-            array_try_into(array![value_31_bytes, value2_31_bytes]), 31
-        );
+        let mut array = ByteArrayImpl::new(array![value_31_bytes, value2_31_bytes], 31);
         assert!(array.len() == 62);
-        assert!(array.pop_front() == Option::Some((value_31_bytes.try_into().unwrap(), 31)));
+        assert!(array.pop_front() == Option::Some((value_31_bytes, 31)));
         assert!(array.len() == 31);
-        assert!(array.pop_front() == Option::Some((value2_31_bytes.try_into().unwrap(), 31)));
+        assert!(array.pop_front() == Option::Some((value2_31_bytes, 31)));
         assert!(array.len() == 0);
         assert!(array.pop_front() == Option::None);
     }
@@ -131,14 +126,14 @@ mod tests {
         let value2_31_bytes = 0x2122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f;
         let value3_5_bytes = 0x4142434445;
         let mut array = ByteArrayImpl::new(
-            array_try_into(array![value_31_bytes, value2_31_bytes, value3_5_bytes]), 5
+            array![value_31_bytes, value2_31_bytes, value3_5_bytes], 5
         );
         assert!(array.len() == 67);
-        assert!(array.pop_front() == Option::Some((value_31_bytes.try_into().unwrap(), 31)));
+        assert!(array.pop_front() == Option::Some((value_31_bytes, 31)));
         assert!(array.len() == 36);
-        assert!(array.pop_front() == Option::Some((value2_31_bytes.try_into().unwrap(), 31)));
+        assert!(array.pop_front() == Option::Some((value2_31_bytes, 31)));
         assert!(array.len() == 5);
-        assert!(array.pop_front() == Option::Some((value3_5_bytes.try_into().unwrap(), 5)));
+        assert!(array.pop_front() == Option::Some((value3_5_bytes, 5)));
         assert!(array.pop_front() == Option::None);
     }
 
@@ -151,18 +146,18 @@ mod tests {
     #[test]
     #[should_panic]
     fn byte_array_last_too_large() {
-        ByteArrayImpl::new(array_try_into(array![1, 2, 3]), 35);
+        ByteArrayImpl::new(array![1, 2, 3], 35);
     }
 
     #[test]
     #[should_panic]
     fn byte_array_last_zero_invalid() {
-        ByteArrayImpl::new(array_try_into(array![1, 2, 0]), 0);
+        ByteArrayImpl::new(array![1, 2, 0], 0);
     }
 
     #[test]
     #[should_panic]
     fn byte_array_last_too_many_bytes() {
-        ByteArrayImpl::new(array_try_into(array![1, 2, 0x010203]), 2);
+        ByteArrayImpl::new(array![1, 2, 0x010203], 2);
     }
 }
diff --git a/target_chains/starknet/contracts/src/reader.cairo b/target_chains/starknet/contracts/src/reader.cairo
index f0501a0f5f..bb41fe9f4a 100644
--- a/target_chains/starknet/contracts/src/reader.cairo
+++ b/target_chains/starknet/contracts/src/reader.cairo
@@ -101,7 +101,7 @@ pub impl ReaderImpl of ReaderTrait {
 
     /// Reads the specified number of bytes as a new byte array.
     fn read_byte_array(ref self: Reader, num_bytes: usize) -> ByteArray {
-        let mut array: Array<bytes31> = array![];
+        let mut array: Array<felt252> = array![];
         let mut num_last_bytes = 0;
         let mut num_remaining_bytes = num_bytes;
         loop {
@@ -173,26 +173,26 @@ impl ReaderPrivateImpl of ReaderPrivateTrait {
 
     // Moved out from `read_bytes` because we cannot use `return` or `?` within a loop.
     fn read_bytes_iteration(
-        ref self: Reader, num_bytes: usize, ref array: Array<bytes31>
+        ref self: Reader, num_bytes: usize, ref array: Array<felt252>
     ) -> (usize, bool) {
         if num_bytes >= 31 {
             let high = self.read_num_bytes(15);
             let low = self.read_num_bytes(16);
             let value: felt252 = u256 { high, low }.try_into().expect(UNEXPECTED_OVERFLOW);
-            array.append(value.try_into().expect(UNEXPECTED_OVERFLOW));
+            array.append(value);
             (31, false)
         } else if num_bytes > 16 {
             // num_bytes < 31
             let high = self.read_num_bytes((num_bytes - 16).try_into().expect(UNEXPECTED_OVERFLOW));
             let low = self.read_num_bytes(16);
             let value: felt252 = u256 { high, low }.try_into().expect(UNEXPECTED_OVERFLOW);
-            array.append(value.try_into().expect(UNEXPECTED_OVERFLOW));
+            array.append(value);
             (num_bytes, true)
         } else {
             // bytes < 16
             let low = self.read_num_bytes(num_bytes.try_into().expect(UNEXPECTED_OVERFLOW));
             let value: felt252 = low.try_into().expect(UNEXPECTED_OVERFLOW);
-            array.append(value.try_into().expect(UNEXPECTED_OVERFLOW));
+            array.append(value);
             (num_bytes, true)
         }
     }
diff --git a/target_chains/starknet/contracts/tests/data.cairo b/target_chains/starknet/contracts/tests/data.cairo
index 306bc5e2b8..065e67517a 100644
--- a/target_chains/starknet/contracts/tests/data.cairo
+++ b/target_chains/starknet/contracts/tests/data.cairo
@@ -48,7 +48,7 @@ pub fn good_update1() -> ByteArray {
         226866843267230707879834616967256711063296411939069440476882347301771901839,
         95752383404870925303422787,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 11)
+    ByteArrayImpl::new(bytes, 11)
 }
 
 // A wormhole VAA from a random update pulled from Hermes.
@@ -86,7 +86,7 @@ pub fn good_vm1() -> ByteArray {
         52685537088250779930155363779405986390839624071318818148325576008719597568,
         14615204155786886573933667335033405822686404253588533,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 22)
+    ByteArrayImpl::new(bytes, 22)
 }
 
 // A first update for a certain timestamp pulled from Hermes.
@@ -134,7 +134,7 @@ pub fn unique_update1() -> ByteArray {
         28583007876111384456149499846085318299326698960792831530075402396150538907,
         126290914008245563820443505,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 11)
+    ByteArrayImpl::new(bytes, 11)
 }
 
 // An actual mainnet wormhole governance VAA from https://github.com/pyth-network/pyth-crosschain/blob/main/contract_manager/src/contracts/wormhole.ts#L32-L37
@@ -159,7 +159,7 @@ pub fn mainnet_guardian_set_upgrade1() -> ByteArray {
         55852237138651071644815135002358067220635692701051811455610533875912981641,
         190413173566657072516608762222993749133,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 16)
+    ByteArrayImpl::new(bytes, 16)
 }
 
 // An actual mainnet wormhole governance VAA from https://github.com/pyth-network/pyth-crosschain/blob/main/contract_manager/src/contracts/wormhole.ts#L32-L37
@@ -210,7 +210,7 @@ pub fn mainnet_guardian_set_upgrade2() -> ByteArray {
         75218391584551901010047495874303520775865073092730040058902770251005073864,
         13453,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 2)
+    ByteArrayImpl::new(bytes, 2)
 }
 
 // An actual mainnet wormhole governance VAA from https://github.com/pyth-network/pyth-crosschain/blob/main/contract_manager/src/contracts/wormhole.ts#L32-L37
@@ -261,7 +261,7 @@ pub fn mainnet_guardian_set_upgrade3() -> ByteArray {
         75218391584551901010047495874303520775865073092730040058902770251005073864,
         13453,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 2)
+    ByteArrayImpl::new(bytes, 2)
 }
 
 // An actual mainnet wormhole governance VAA from https://github.com/pyth-network/pyth-crosschain/blob/main/contract_manager/src/contracts/wormhole.ts#L32-L37
@@ -312,7 +312,7 @@ pub fn mainnet_guardian_set_upgrade4() -> ByteArray {
         75218391584551901010047495874303520775865073092730040058902770251005073864,
         13453,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 2)
+    ByteArrayImpl::new(bytes, 2)
 }
 
 pub const TEST_GUARDIAN_ADDRESS1: felt252 = 0x686b9ea8e3237110eaaba1f1b7467559a3273819;
@@ -328,7 +328,7 @@ pub fn empty_set_upgrade() -> ByteArray {
         1131377253,
         210141960835432704,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 8)
+    ByteArrayImpl::new(bytes, 8)
 }
 
 // A wormhole guardian set upgrade instruction with emitter not expected by the test.
@@ -341,7 +341,7 @@ pub fn wrong_emitter_upgrade() -> ByteArray {
         1131377253,
         307122819832911374634462256129025725147663742791077927773782095897,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 28)
+    ByteArrayImpl::new(bytes, 28)
 }
 
 // A wormhole guardian set upgrade instruction with set index = 3 not expected by the test.
@@ -354,7 +354,7 @@ pub fn wrong_index_upgrade() -> ByteArray {
         1131377253,
         210624583337115497886730203944140689990237281548333499058561169433,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 28)
+    ByteArrayImpl::new(bytes, 28)
 }
 
 // A wormhole governance guardian set upgrade instruction signed by test guardian #1 containing test guardian #2 as the new guardian set.
@@ -367,7 +367,7 @@ pub fn upgrade_to_test2() -> ByteArray {
         1131377253,
         210624583337114749311237613435643962969294824395451022190048752713,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 28)
+    ByteArrayImpl::new(bytes, 28)
 }
 
 // A Pyth governance instruction to set fee signed by the test guardian #1.
@@ -379,7 +379,7 @@ pub fn pyth_set_fee() -> ByteArray {
         49565958604199796163020368,
         8072278384728444780182694421117884443886221966887092226,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 23)
+    ByteArrayImpl::new(bytes, 23)
 }
 
 // A Pyth governance instruction to set data sources signed by the test guardian #1.
@@ -393,7 +393,7 @@ pub fn pyth_set_data_sources() -> ByteArray {
         223938022913800988696085410923418445187967252047785407181969631814277398528,
         301,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 14)
+    ByteArrayImpl::new(bytes, 14)
 }
 
 // A Pyth governance instruction to set wormhole address signed by the test guardian #1.
@@ -406,7 +406,7 @@ pub fn pyth_set_wormhole() -> ByteArray {
         148907253456057279176930315687485033494639386197985334929728922792833758561,
         3789456330195130818,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 8)
+    ByteArrayImpl::new(bytes, 8)
 }
 
 // A Pyth governance instruction to request governance data source transfer signed by the test guardian #1.
@@ -418,7 +418,7 @@ pub fn pyth_request_transfer() -> ByteArray {
         51983810243429054512432720,
         101886477340929157123538945,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 11)
+    ByteArrayImpl::new(bytes, 11)
 }
 
 // A Pyth governance instruction to authorize governance data source transfer signed by the test guardian #1.
@@ -434,7 +434,7 @@ pub fn pyth_auth_transfer() -> ByteArray {
         721420288,
         20782639266000304984163621011457,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 18)
+    ByteArrayImpl::new(bytes, 18)
 }
 
 // A Pyth governance instruction to set fee with alternative emitter signed by the test guardian #1.
@@ -446,7 +446,7 @@ pub fn pyth_set_fee_alt_emitter() -> ByteArray {
         51983810243429054512498256,
         8072278384728444780182694421117884443886221966887092226,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 23)
+    ByteArrayImpl::new(bytes, 23)
 }
 
 // A Pyth governance instruction to upgrade the contract signed by the test guardian #1.
@@ -459,7 +459,7 @@ pub fn pyth_upgrade_fake1() -> ByteArray {
         148907253453589022320407306335457538262203456299261498528172020674942501293,
         9624434269354675143,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 8)
+    ByteArrayImpl::new(bytes, 8)
 }
 
 // A Pyth governance instruction to upgrade the contract signed by the test guardian #1.
@@ -472,7 +472,7 @@ pub fn pyth_upgrade_not_pyth() -> ByteArray {
         148907253453589022305803196061110108233921773465491227564264876752079119569,
         6736708290019375278,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 8)
+    ByteArrayImpl::new(bytes, 8)
 }
 
 // A Pyth governance instruction to upgrade the contract signed by the test guardian #1.
@@ -485,7 +485,7 @@ pub fn pyth_upgrade_wrong_magic() -> ByteArray {
         148907253453589022340563264373887392414227070562033595690783947835630084766,
         5698494087895763928,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 8)
+    ByteArrayImpl::new(bytes, 8)
 }
 
 // A Pyth governance instruction to upgrade the contract signed by the test guardian #1.
@@ -498,7 +498,7 @@ pub fn pyth_upgrade_invalid_hash() -> ByteArray {
         148907253453589022218037939353255655322518022029545083499057126097303896064,
         505,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 8)
+    ByteArrayImpl::new(bytes, 8)
 }
 
 // An update pulled from Hermes and re-signed by the test guardian #1.
@@ -520,7 +520,7 @@ pub fn test_price_update1() -> ByteArray {
         87135893730137265929093180553063146337041045646221968026289709394440932141,
         245333243912241114598596888050489286502591033459250287888834,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 25)
+    ByteArrayImpl::new(bytes, 25)
 }
 
 // An update pulled from Hermes and re-signed by the test guardian #1.
@@ -542,7 +542,7 @@ pub fn test_price_update2() -> ByteArray {
         370855179649505412564259994413632062925303311800103998016489412083011059699,
         1182295126766215829784496273374889928477877265080355104888778,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 25)
+    ByteArrayImpl::new(bytes, 25)
 }
 
 // An update pulled from Hermes and re-signed by the test guardian #1 with another emitter address.
@@ -564,7 +564,7 @@ pub fn test_update2_alt_emitter() -> ByteArray {
         370855179649505412564259994413632062925303311800103998016489412083011059699,
         1182295126766215829784496273374889928477877265080355104888778,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 25)
+    ByteArrayImpl::new(bytes, 25)
 }
 
 // An update pulled from Hermes and re-signed by the test guardian #2.
@@ -586,5 +586,5 @@ pub fn test_update2_set2() -> ByteArray {
         370855179649505412564259994413632062925303311800103998016489412083011059699,
         1182295126766215829784496273374889928477877265080355104888778,
     ];
-    ByteArrayImpl::new(array_try_into(bytes), 25)
+    ByteArrayImpl::new(bytes, 25)
 }
diff --git a/target_chains/starknet/contracts/tests/wormhole.cairo b/target_chains/starknet/contracts/tests/wormhole.cairo
index 34968ebbb7..301f5e6015 100644
--- a/target_chains/starknet/contracts/tests/wormhole.cairo
+++ b/target_chains/starknet/contracts/tests/wormhole.cairo
@@ -8,7 +8,7 @@ use pyth::wormhole::{
 };
 use pyth::reader::ReaderImpl;
 use pyth::byte_array::{ByteArray, ByteArrayImpl};
-use pyth::util::{UnwrapWithFelt252, array_try_into};
+use pyth::util::{UnwrapWithFelt252, array_try_into, one_shift_left_bytes_u256};
 use core::starknet::{ContractAddress, EthAddress};
 use core::panic_with_felt252;
 use super::data;
@@ -352,16 +352,18 @@ pub fn corrupted_vm(
     ByteArrayImpl::new(new_data, num_last_bytes)
 }
 
-// Returns a `bytes31` value with 2 bytes changed. We need to change at least 2 bytes
+// Returns an item of ByteArray data with 2 bytes changed. We need to change at least 2 bytes
 // because a single byte can be a recovery id, where only 1 bit matters so
 // a modification of recovery id can result in a valid VM.
-fn corrupted_bytes(input: bytes31, index: usize, random1: usize, random2: usize) -> bytes31 {
+fn corrupted_bytes(input: felt252, index: usize, random1: usize, random2: usize) -> felt252 {
     let index2 = (index + 1) % 31;
+    let input: u256 = input.into();
 
     let mut value: u256 = 0;
-    let mut i = 0;
+    let mut i: usize = 0;
     while i < 31 {
-        let real_byte = input.at(30 - i);
+        let real_byte = (input / one_shift_left_bytes_u256(30 - i.try_into().unwrap())) % 0x100;
+        let real_byte: u8 = real_byte.try_into().unwrap();
         let new_byte = if i == index {
             corrupted_byte(real_byte, random1)
         } else if i == index2 {
diff --git a/target_chains/starknet/tools/test_vaas/src/lib.rs b/target_chains/starknet/tools/test_vaas/src/lib.rs
index 00d9dbdaba..6e928b1e6c 100644
--- a/target_chains/starknet/tools/test_vaas/src/lib.rs
+++ b/target_chains/starknet/tools/test_vaas/src/lib.rs
@@ -66,10 +66,7 @@ pub fn print_as_cairo_fn(data: &[u8], name: impl Display, comment: impl Display)
         println!("        {item},");
     }
     println!("    ];");
-    println!(
-        "    ByteArrayImpl::new(array_try_into(bytes), {})",
-        data.num_last_bytes
-    );
+    println!("    ByteArrayImpl::new(bytes, {})", data.num_last_bytes);
     println!("}}");
 }