diff --git a/evm/src/cpu/kernel/asm/memory/metadata.asm b/evm/src/cpu/kernel/asm/memory/metadata.asm
index f00fbce6..caa76051 100644
--- a/evm/src/cpu/kernel/asm/memory/metadata.asm
+++ b/evm/src/cpu/kernel/asm/memory/metadata.asm
@@ -249,7 +249,7 @@ global blockhash:
     // stack: cur_block_number, block_number, retdest
     DUP1 DUP3 %increment GT %jumpi(zero_hash) // if block_number >= cur_block_number
     // stack: cur_block_number, block_number, retdest
-    DUP2 PUSH 256 ADD 
+    DUP2 PUSH 256 %add_or_fault
     // stack: block_number+256, cur_block_number, block_number, retdest
     DUP2 GT %jumpi(zero_hash) // if cur_block_number > block_number + 256
     // If we are here, the provided block number is correct
diff --git a/evm/src/cpu/kernel/tests/block_hash.rs b/evm/src/cpu/kernel/tests/block_hash.rs
index 98d23108..bf1932a0 100644
--- a/evm/src/cpu/kernel/tests/block_hash.rs
+++ b/evm/src/cpu/kernel/tests/block_hash.rs
@@ -76,7 +76,7 @@ fn test_small_index_block_hash() -> Result<()> {
     let block_number = rng.gen::<u8>() as usize;
     let initial_stack = vec![retdest, block_number.into()];
 
-    let hashes: Vec<U256> = (20..277).map(|elt| elt.into()).collect();
+    let hashes: Vec<U256> = vec![U256::from_big_endian(&thread_rng().gen::<H256>().0); 257];
 
     let mut interpreter = Interpreter::new_with_kernel(blockhash_label, initial_stack);
     interpreter.set_memory_segment(Segment::BlockHashes, hashes[0..256].to_vec());
@@ -95,3 +95,21 @@ fn test_small_index_block_hash() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+#[should_panic]
+fn test_block_hash_with_overflow() {
+    let blockhash_label = KERNEL.global_labels["blockhash"];
+    let retdest = 0xDEADBEEFu32.into();
+    let cur_block_number = 1;
+    let block_number = U256::MAX;
+    let initial_stack = vec![retdest, block_number];
+
+    let hashes: Vec<U256> = vec![U256::from_big_endian(&thread_rng().gen::<H256>().0); 257];
+
+    let mut interpreter = Interpreter::new_with_kernel(blockhash_label, initial_stack);
+    interpreter.set_memory_segment(Segment::BlockHashes, hashes[0..256].to_vec());
+    interpreter.set_global_metadata_field(GlobalMetadata::BlockCurrentHash, hashes[256]);
+    interpreter.set_global_metadata_field(GlobalMetadata::BlockNumber, cur_block_number.into());
+    let _ = interpreter.run();
+}
diff --git a/evm/src/generation/mod.rs b/evm/src/generation/mod.rs
index 7c69b8dd..d495f342 100644
--- a/evm/src/generation/mod.rs
+++ b/evm/src/generation/mod.rs
@@ -104,7 +104,7 @@ fn apply_metadata_and_tries_memops<F: RichField + Extendable<D>, const D: usize>
         (GlobalMetadata::BlockBaseFee, metadata.block_base_fee),
         (
             GlobalMetadata::BlockCurrentHash,
-            U256::from_big_endian(&inputs.block_hashes.cur_hash.0),
+            h2u(inputs.block_hashes.cur_hash),
         ),
         (GlobalMetadata::BlockGasUsed, metadata.block_gas_used),
         (GlobalMetadata::BlockGasUsedBefore, inputs.gas_used_before),
diff --git a/evm/src/get_challenges.rs b/evm/src/get_challenges.rs
index c32b8964..d2405b8b 100644
--- a/evm/src/get_challenges.rs
+++ b/evm/src/get_challenges.rs
@@ -13,7 +13,7 @@ use crate::permutation::{
     get_n_grand_product_challenge_sets_target,
 };
 use crate::proof::*;
-use crate::util::u256_limbs;
+use crate::util::{h256_limbs, u256_limbs};
 
 fn observe_root<F: RichField + Extendable<D>, C: GenericConfig<D, F = F>, const D: usize>(
     challenger: &mut Challenger<F, C::Hasher>,
@@ -155,12 +155,9 @@ fn observe_block_hashes<
     block_hashes: &BlockHashes,
 ) {
     for i in 0..256 {
-        challenger.observe_elements(
-            &u256_limbs::<F>(U256::from_big_endian(&block_hashes.prev_hashes[i].0))[0..8],
-        );
+        challenger.observe_elements(&h256_limbs::<F>(block_hashes.prev_hashes[i])[0..8]);
     }
-    challenger
-        .observe_elements(&u256_limbs::<F>(U256::from_big_endian(&block_hashes.cur_hash.0))[0..8])
+    challenger.observe_elements(&h256_limbs::<F>(block_hashes.cur_hash)[0..8])
 }
 
 fn observe_block_hashes_target<
diff --git a/evm/src/recursive_verifier.rs b/evm/src/recursive_verifier.rs
index 320b4341..66708318 100644
--- a/evm/src/recursive_verifier.rs
+++ b/evm/src/recursive_verifier.rs
@@ -43,7 +43,7 @@ use crate::proof::{
     TrieRootsTarget,
 };
 use crate::stark::Stark;
-use crate::util::u256_limbs;
+use crate::util::{h256_limbs, u256_limbs};
 use crate::vanishing_poly::eval_vanishing_poly_circuit;
 use crate::vars::StarkEvaluationTargets;
 
@@ -1057,19 +1057,17 @@ pub(crate) fn set_block_hashes_target<F, W, const D: usize>(
     W: Witness<F>,
 {
     for i in 0..256 {
-        let block_hash_limbs: [F; 8] =
-            u256_limbs::<F>(U256::from_big_endian(&block_hashes.prev_hashes[i].0))[..8]
-                .try_into()
-                .unwrap();
+        let block_hash_limbs: [F; 8] = h256_limbs::<F>(block_hashes.prev_hashes[i])[..8]
+            .try_into()
+            .unwrap();
         witness.set_target_arr(
             &block_hashes_target.prev_hashes[8 * i..8 * (i + 1)],
             &block_hash_limbs,
         );
     }
-    let cur_block_hash_limbs: [F; 8] =
-        u256_limbs::<F>(U256::from_big_endian(&block_hashes.cur_hash.0))[..8]
-            .try_into()
-            .unwrap();
+    let cur_block_hash_limbs: [F; 8] = h256_limbs::<F>(block_hashes.cur_hash)[..8]
+        .try_into()
+        .unwrap();
     witness.set_target_arr(&block_hashes_target.cur_hash, &cur_block_hash_limbs);
 }
 
diff --git a/evm/src/verifier.rs b/evm/src/verifier.rs
index 1d93670a..ff3a246a 100644
--- a/evm/src/verifier.rs
+++ b/evm/src/verifier.rs
@@ -178,7 +178,7 @@ where
         ),
         (
             GlobalMetadata::BlockCurrentHash,
-            U256::from_big_endian(&public_values.block_hashes.cur_hash.0),
+            h2u(public_values.block_hashes.cur_hash),
         ),
         (
             GlobalMetadata::BlockGasUsed,