diff --git a/.github/workflows/pr-main_l1.yaml b/.github/workflows/pr-main_l1.yaml
index f1962402b8..271a444a34 100644
--- a/.github/workflows/pr-main_l1.yaml
+++ b/.github/workflows/pr-main_l1.yaml
@@ -126,6 +126,24 @@ jobs:
         run: |
           make -C tooling/ef_tests/blockchain test
 
+  test-stateless-zkevm:
+    name: Test - Stateless zkEVM
+    needs: detect-changes
+    if: ${{ needs.detect-changes.outputs.run_tests == 'true' && github.event_name != 'merge_group' }}
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+
+      - name: Free Disk Space
+        uses: ./.github/actions/free-disk
+
+      - name: Setup Rust Environment
+        uses: ./.github/actions/setup-rust
+
+      - name: Run Blockchain EF tests
+        run: make -C tooling/ef_tests/blockchain test-stateless-zkevm
+
   docker_build:
     name: Build Docker
     runs-on: ubuntu-latest
diff --git a/crates/common/types/block_execution_witness.rs b/crates/common/types/block_execution_witness.rs
index 71071764fa..86e51a5bb5 100644
--- a/crates/common/types/block_execution_witness.rs
+++ b/crates/common/types/block_execution_witness.rs
@@ -151,16 +151,27 @@ impl RpcExecutionWitness {
             ));
         }
 
-        let mut initial_state_root = None;
-
-        for h in &self.headers {
-            let header = BlockHeader::decode(h)?;
-            if header.number == first_block_number - 1 {
-                initial_state_root = Some(header.state_root);
-                break;
+        // Decode headers up front so we can validate the ordering invariant:
+        // an RPC witness must provide headers in ascending, contiguous block-number
+        // order. Reordered or gapped inputs would otherwise be silently normalized
+        // by the BTreeMap in `GuestProgramState::from_witness` and yield an
+        // incorrect conclusion about the block's validity.
+        let decoded_headers: Vec<BlockHeader> = self
+            .headers
+            .iter()
+            .map(|h| BlockHeader::decode(h))
+            .collect::<Result<_, _>>()?;
+        for window in decoded_headers.windows(2) {
+            if window[1].number != window[0].number + 1 {
+                return Err(GuestProgramStateError::NoncontiguousBlockHeaders);
             }
         }
 
+        let initial_state_root = decoded_headers
+            .iter()
+            .find(|h| h.number == first_block_number - 1)
+            .map(|h| h.state_root);
+
         let initial_state_root = initial_state_root.ok_or_else(|| {
             GuestProgramStateError::Custom(format!(
                 "header for block {} not found",
@@ -177,10 +188,13 @@ impl RpcExecutionWitness {
                     // which would fail to decode in ours
                     return None;
                 }
+                // Tolerate extra unused witness entries that don't decode as trie nodes.
+                // Nodes that are actually needed for state access are looked up by hash
+                // later; extra junk cannot be referenced.
                 let hash = keccak(&b);
-                Some(Node::decode(&b).map(|node| (hash, node)))
+                Node::decode(&b).ok().map(|node| (hash, node))
             })
-            .collect::<Result<_, RLPDecodeError>>()?;
+            .collect();
 
         // get state trie root and embed the rest of the trie into it
         let state_trie_root = if let NodeRef::Node(state_trie_root, _) =
@@ -589,28 +603,25 @@ impl GuestProgramState {
     }
 
     /// Retrieves the account code for a specific account.
-    /// Returns an Err if the code is not found.
+    /// Returns an Err if the code is not found — a missing code hash means
+    /// the execution witness is invalid and the guest program must not
+    /// conclude anything about the state.
     pub fn get_account_code(&self, code_hash: H256) -> Result<Code, GuestProgramStateError> {
         if code_hash == *EMPTY_KECCACK_HASH {
             return Ok(Code::default());
         }
-        match self.codes_hashed.get(&code_hash) {
-            Some(code) => Ok(code.clone()),
-            None => {
-                // We do this because what usually happens is that the Witness doesn't have the code we asked for but it is because it isn't relevant for that particular case.
-                // In client implementations there are differences and it's natural for some clients to access more/less information in some edge cases.
-                // Sidenote: logger doesn't work inside SP1, that's why we use println!
-                println!(
-                    "Missing bytecode for hash {} in witness. Defaulting to empty code.", // If there's a state root mismatch and this prints we have to see if it's the cause or not.
-                    hex::encode(code_hash)
-                );
-                Ok(Code::default())
-            }
-        }
+        self.codes_hashed.get(&code_hash).cloned().ok_or_else(|| {
+            GuestProgramStateError::Custom(format!(
+                "missing bytecode for hash {} in execution witness",
+                hex::encode(code_hash)
+            ))
+        })
     }
 
     /// Retrieves code metadata (length) for a specific code hash.
     /// This is an optimized path for EXTCODESIZE opcode.
+    /// Returns an Err if the code is not found — same rationale as
+    /// [`Self::get_account_code`].
     pub fn get_code_metadata(
         &self,
         code_hash: H256,
@@ -620,19 +631,17 @@ impl GuestProgramState {
         if code_hash == *EMPTY_KECCACK_HASH {
             return Ok(CodeMetadata { length: 0 });
         }
-        match self.codes_hashed.get(&code_hash) {
-            Some(code) => Ok(CodeMetadata {
+        self.codes_hashed
+            .get(&code_hash)
+            .map(|code| CodeMetadata {
                 length: code.bytecode.len() as u64,
-            }),
-            None => {
-                // Same as get_account_code - default to empty for missing bytecode
-                println!(
-                    "Missing bytecode for hash {} in witness. Defaulting to empty code metadata.",
+            })
+            .ok_or_else(|| {
+                GuestProgramStateError::Custom(format!(
+                    "missing bytecode for hash {} in execution witness",
                     hex::encode(code_hash)
-                );
-                Ok(CodeMetadata { length: 0 })
-            }
-        }
+                ))
+            })
     }
 
     /// When executing multiple blocks in the L2 it happens that the headers in block_headers correspond to the same block headers that we have in the blocks array. The main goal is to hash these only once and set them in both places.
diff --git a/tooling/ef_tests/blockchain/.fixtures_url_zkevm b/tooling/ef_tests/blockchain/.fixtures_url_zkevm
index 7b92a046c9..1c4b11fd86 100644
--- a/tooling/ef_tests/blockchain/.fixtures_url_zkevm
+++ b/tooling/ef_tests/blockchain/.fixtures_url_zkevm
@@ -1 +1 @@
-https://github.com/ethereum/execution-spec-tests/releases/download/zkevm%40v0.3.0/fixtures_zkevm.tar.gz
+https://github.com/ethereum/execution-spec-tests/releases/download/zkevm%40v0.3.3/fixtures_zkevm.tar.gz
diff --git a/tooling/ef_tests/blockchain/test_runner.rs b/tooling/ef_tests/blockchain/test_runner.rs
index 85fac6dd9b..9740ed2fba 100644
--- a/tooling/ef_tests/blockchain/test_runner.rs
+++ b/tooling/ef_tests/blockchain/test_runner.rs
@@ -529,6 +529,11 @@ async fn re_run_stateless(
 /// trie nodes, codes, and ancestor headers needed for that specific block.
 /// Following the spec, we execute each block
 /// independently with its own witness.
+///
+/// The fixture's `statelessOutputBytes` encodes the expected output as
+/// `new_payload_request_root (32 bytes) || valid (1 byte) || padding`. When
+/// `valid == 0`, the witness is intentionally invalid and stateless execution
+/// is expected to fail (or conclude the block is invalid).
 #[cfg(feature = "stateless")]
 async fn run_stateless_from_fixture(
     test: &TestUnit,
@@ -551,6 +556,9 @@ async fn run_stateless_from_fixture(
             continue;
         };
 
+        let expect_stateless_valid =
+            expected_stateless_valid(block_data.stateless_output_bytes.as_deref());
+
         let block: CoreBlock = block_data.clone().into();
         let block_number = block.header.number;
 
@@ -559,9 +567,21 @@ async fn run_stateless_from_fixture(
                 format!("Failed to parse executionWitness for block {block_number}: {e}")
             })?;
 
-        let execution_witness = rpc_witness
-            .into_execution_witness(*chain_config, block_number)
-            .map_err(|e| format!("Witness conversion failed for block {block_number}: {e}"))?;
+        let witness_conversion_result =
+            rpc_witness.into_execution_witness(*chain_config, block_number);
+        let execution_witness = match witness_conversion_result {
+            Ok(w) => w,
+            Err(e) => {
+                // An intentionally invalid witness may fail conversion — that's a valid
+                // "block is invalid" conclusion when the fixture marks this block invalid.
+                if !expect_stateless_valid {
+                    continue;
+                }
+                return Err(format!(
+                    "Witness conversion failed for block {block_number}: {e}"
+                ));
+            }
+        };
 
         let program_input = ProgramInput::new(vec![block], execution_witness);
 
@@ -571,12 +591,39 @@ async fn run_stateless_from_fixture(
             BackendType::SP1 => Sp1Backend::new().execute(program_input),
         };
 
-        if let Err(e) = execute_result {
-            return Err(format!(
-                "Stateless execution from fixture failed for {test_key} block {block_number}: {e}"
-            ));
+        match execute_result {
+            Ok(()) => {
+                if !expect_stateless_valid {
+                    return Err(format!(
+                        "Expected stateless execution to fail for {test_key} block {block_number} (fixture valid=0x00) but it succeeded"
+                    ));
+                }
+            }
+            Err(e) => {
+                if expect_stateless_valid {
+                    return Err(format!(
+                        "Stateless execution from fixture failed for {test_key} block {block_number}: {e}"
+                    ));
+                }
+            }
         }
     }
 
     Ok(())
 }
+
+/// Parse the `valid` flag (byte 32) from a fixture's `statelessOutputBytes`.
+///
+/// Layout: `new_payload_request_root (32 bytes) || valid (1 byte) || padding`.
+/// If absent or unparseable, default to expecting success (true) to preserve
+/// the prior behavior for fixtures without this field.
+#[cfg(feature = "stateless")]
+fn expected_stateless_valid(hex_str: Option<&str>) -> bool {
+    let Some(s) = hex_str else { return true };
+    let s = s.strip_prefix("0x").unwrap_or(s);
+    // valid byte is at hex offset 64..66 (bytes[32])
+    match s.get(64..66).and_then(|b| u8::from_str_radix(b, 16).ok()) {
+        Some(0) => false,
+        _ => true,
+    }
+}