diff --git a/packages/engine/src/errors.cairo b/packages/engine/src/errors.cairo
index 4754e7f..c87aec2 100644
--- a/packages/engine/src/errors.cairo
+++ b/packages/engine/src/errors.cairo
@@ -17,7 +17,6 @@ pub mod Error {
     pub const UNSATISFIED_LOCKTIME: felt252 = 'Unsatisfied locktime';
     pub const SCRIPT_STRICT_MULTISIG: felt252 = 'OP_CHECKMULTISIG invalid dummy';
     pub const FINALIZED_TX_CLTV: felt252 = 'Finalized tx in OP_CLTV';
-    pub const INVALID_TX_VERSION: felt252 = 'Invalid transaction version';
     pub const SCRIPT_INVALID: felt252 = 'Invalid script data';
     pub const INVALID_COINBASE: felt252 = 'Invalid coinbase transaction';
     pub const SIG_NULLFAIL: felt252 = 'Sig non-zero on failed checksig';
@@ -50,6 +49,7 @@ pub mod Error {
     pub const SIG_HIGH_S: felt252 = 'Sig not canonical high S value';
     pub const SIG_HASHTYPE: felt252 = 'invalid hash type';
     pub const INVALID_PUBKEY_LEN: felt252 = 'Invalid public key length';
+    pub const NEGATIVE_LOCKTIME: felt252 = 'Stack top is negative';
 }
 
 pub fn byte_array_err(err: felt252) -> ByteArray {
diff --git a/packages/engine/src/opcodes/locktime.cairo b/packages/engine/src/opcodes/locktime.cairo
index 4cd068c..8921df9 100644
--- a/packages/engine/src/opcodes/locktime.cairo
+++ b/packages/engine/src/opcodes/locktime.cairo
@@ -107,14 +107,14 @@ pub fn opcode_checksequenceverify<
     )?;
 
     if stack_sequence < 0 {
-        return Result::Err(Error::UNSATISFIED_LOCKTIME);
+        return Result::Err(Error::NEGATIVE_LOCKTIME);
     }
 
     // Redefine 'stack_sequence' to perform bitwise operation easily
-    let stack_sequence_u32: u32 = stack_sequence.try_into().unwrap();
+    let stack_sequence_u64: u64 = stack_sequence.try_into().unwrap();
 
     // Disabled bit set in 'stack_sequence' result as OP_NOP behavior
-    if stack_sequence_u32 & SEQUENCE_LOCKTIME_DISABLED != 0 {
+    if stack_sequence_u64 & SEQUENCE_LOCKTIME_DISABLED.into() != 0 {
         return Result::Ok(());
     }
 
@@ -123,7 +123,7 @@ pub fn opcode_checksequenceverify<
         T, I, O, IEngineTransactionInputTrait, IEngineTransactionOutputTrait
     >::get_version(engine.transaction);
     if version < 2 {
-        return Result::Err(Error::INVALID_TX_VERSION);
+        return Result::Err(Error::UNSATISFIED_LOCKTIME);
     }
 
     let transaction_input = EngineTransactionTrait::<
@@ -142,6 +142,6 @@ pub fn opcode_checksequenceverify<
     verify_locktime(
         (tx_sequence & locktime_mask).into(),
         SEQUENCE_LOCKTIME_IS_SECOND.into(),
-        (stack_sequence_u32 & locktime_mask).into()
+        (stack_sequence_u64 & locktime_mask.into()).try_into().unwrap()
     )
 }
diff --git a/packages/tests/src/tests/opcodes/test_locktime.cairo b/packages/tests/src/tests/opcodes/test_locktime.cairo
index 4951609..91f837c 100644
--- a/packages/tests/src/tests/opcodes/test_locktime.cairo
+++ b/packages/tests/src/tests/opcodes/test_locktime.cairo
@@ -156,7 +156,7 @@ fn test_opcode_checksequence_tx_version_fail() {
     // Running with tx v1
     let flags: u32 = ScriptFlags::ScriptVerifyCheckSequenceVerify.into();
     let mut engine = utils::test_compile_and_run_with_tx_flags_err(
-        program, tx, flags, Error::INVALID_TX_VERSION
+        program, tx, flags, Error::UNSATISFIED_LOCKTIME
     );
     utils::check_dstack_size(ref engine, 1);
 }
diff --git a/tests/run-core-tests.sh b/tests/run-core-tests.sh
index 08406a2..cb3902e 100755
--- a/tests/run-core-tests.sh
+++ b/tests/run-core-tests.sh
@@ -146,7 +146,8 @@ jq -c '.[]' $SCRIPT_TESTS_JSON | {
         PUBKEYTYPE="Execution failed: Unsupported public key type"
         INVALID_SIG_FMT="Execution failed: invalid sig fmt: too short"
         INVALID_HASH_TYPE="Execution failed: invalid hash type"
-        INVALID_LOCKTIME="Execution failed: Unsatisfied locktime"
+        NEGATIVE_LOCKTIME="Execution failed: Stack top is negative"
+        UNSATISFIED_LOCKTIME="Execution failed: Unsatisfied locktime"
         SCRIPT_SIZE="Execution failed: Engine::new: script too large"
         CLEAN_STACK="Execution failed: Non-clean stack after execute"
         MINIMAL_DATA="Execution failed: Opcode represents non-minimal"
@@ -220,8 +221,10 @@ jq -c '.[]' $SCRIPT_TESTS_JSON | {
             SCRIPT_RESULT="PUSH_SIZE"
         elif echo "$RESULT" | grep -q "$OP_COUNT"; then
             SCRIPT_RESULT="OP_COUNT"
-        elif echo "$RESULT" | grep -q "$INVALID_LOCKTIME"; then
+        elif echo "$RESULT" | grep -q "$NEGATIVE_LOCKTIME"; then
             SCRIPT_RESULT="NEGATIVE_LOCKTIME"
+        elif echo "$RESULT" | grep -q "$UNSATISFIED_LOCKTIME"; then
+            SCRIPT_RESULT="UNSATISFIED_LOCKTIME"
         elif echo "$RESULT" | grep -q "$SCRIPT_SIZE"; then
             SCRIPT_RESULT="SCRIPT_SIZE"
         elif echo "$RESULT" | grep -q "$CLEAN_STACK"; then
diff --git a/tests/run-failing-core-tests.sh b/tests/run-failing-core-tests.sh
index 2efc8f3..cc5ef19 100755
--- a/tests/run-failing-core-tests.sh
+++ b/tests/run-failing-core-tests.sh
@@ -131,7 +131,8 @@ jq -c '.[]' $SCRIPT_TESTS_JSON | {
         PUBKEYTYPE="Execution failed: Unsupported public key type"
         INVALID_SIG_FMT="Execution failed: invalid sig fmt: too short"
         INVALID_HASH_TYPE="Execution failed: invalid hash type"
-        INVALID_LOCKTIME="Execution failed: Unsatisfied locktime"
+        NEGATIVE_LOCKTIME="Execution failed: Stack top is negative"
+        UNSATISFIED_LOCKTIME="Execution failed: Unsatisfied locktime"
         SCRIPT_SIZE="Execution failed: Engine::new: script too large"
         CLEAN_STACK="Execution failed: Non-clean stack after execute"
         MINIMAL_DATA="Execution failed: Opcode represents non-minimal"
@@ -198,7 +199,9 @@ jq -c '.[]' $SCRIPT_TESTS_JSON | {
             SCRIPT_RESULT="PUSH_SIZE"
         elif echo "$RESULT" | grep -q "$OP_COUNT"; then
             SCRIPT_RESULT="OP_COUNT"
-        elif echo "$RESULT" | grep -q "$INVALID_LOCKTIME"; then
+        elif echo "$RESULT" | grep -q "$UNSATISFIED_LOCKTIME"; then
+            SCRIPT_RESULT="UNSATISFIED_LOCKTIME"
+        elif echo "$RESULT" | grep -q "$NEGATIVE_LOCKTIME"; then
             SCRIPT_RESULT="NEGATIVE_LOCKTIME"
         elif echo "$RESULT" | grep -q "$SCRIPT_SIZE"; then
             SCRIPT_RESULT="SCRIPT_SIZE"
diff --git a/tests/script_tests_failing.json b/tests/script_tests_failing.json
index db0f3ca..fe51488 100644
--- a/tests/script_tests_failing.json
+++ b/tests/script_tests_failing.json
@@ -1,3 +1 @@
-[
-["0","CHECKSEQUENCEVERIFY","CHECKSEQUENCEVERIFY","UNSATISFIED_LOCKTIME","CSV fails if stack top bit 1 << 31 is set and the tx version < 2"],
-["0x050000000001","CHECKSEQUENCEVERIFY","CHECKSEQUENCEVERIFY","UNSATISFIED_LOCKTIME","CSV fails if stack top bit 1 << 31 is not set, and tx version < 2"]]
+[]
diff --git a/tests/script_tests_passing.json b/tests/script_tests_passing.json
index fa56d07..1c41d62 100644
--- a/tests/script_tests_passing.json
+++ b/tests/script_tests_passing.json
@@ -1126,6 +1126,8 @@
 ["","CHECKSEQUENCEVERIFY","CHECKSEQUENCEVERIFY","INVALID_STACK_OPERATION","CSV automatically fails on an empty stack"],
 ["-1","CHECKSEQUENCEVERIFY","CHECKSEQUENCEVERIFY","NEGATIVE_LOCKTIME","CSV automatically fails if stack top is negative"],
 ["0x0100","CHECKSEQUENCEVERIFY","CHECKSEQUENCEVERIFY,MINIMALDATA","UNKNOWN_ERROR","CSV fails if stack top is not minimally encoded"],
+["0","CHECKSEQUENCEVERIFY","CHECKSEQUENCEVERIFY","UNSATISFIED_LOCKTIME","CSV fails if stack top bit 1 << 31 is set and the tx version < 2"],
+["0x050000000001","CHECKSEQUENCEVERIFY","CHECKSEQUENCEVERIFY","UNSATISFIED_LOCKTIME","CSV fails if stack top bit 1 << 31 is not set, and tx version < 2"],
 ["1","IF 1 ENDIF","P2SH,WITNESS,MINIMALIF","OK"],
 ["2","IF 1 ENDIF","P2SH,WITNESS,MINIMALIF","OK"],
 ["0x02 0x0100","IF 1 ENDIF","P2SH,WITNESS,MINIMALIF","OK"],