diff --git a/beacon_node/http_api/src/block_id.rs b/beacon_node/http_api/src/block_id.rs
index ea8b47f91ef..6a0cdc33a08 100644
--- a/beacon_node/http_api/src/block_id.rs
+++ b/beacon_node/http_api/src/block_id.rs
@@ -483,8 +483,9 @@ impl BlockId {
                 },
             )
         } else {
-            Err(warp_utils::reject::custom_server_error(format!(
-                "Insufficient data columns to reconstruct blobs: required {num_required_columns}, but only {num_found_column_keys} were found."
+            Err(warp_utils::reject::custom_bad_request(format!(
+                "Insufficient data columns to reconstruct blobs: required {num_required_columns}, but only {num_found_column_keys} were found. \
+                You may need to run the beacon node with --supernode or --semi-supernode."
             )))
         }
     }
diff --git a/beacon_node/http_api/tests/tests.rs b/beacon_node/http_api/tests/tests.rs
index ed7abead18a..72e21869596 100644
--- a/beacon_node/http_api/tests/tests.rs
+++ b/beacon_node/http_api/tests/tests.rs
@@ -1970,8 +1970,8 @@ impl ApiTester {
             .await
         {
             Ok(result) => panic!("Full node are unable to return blobs post-Fulu: {result:?}"),
-            // Post-Fulu, full nodes don't store blobs and return error 500
-            Err(e) => assert_eq!(e.status().unwrap(), 500),
+            // Post-Fulu, full nodes don't store blobs and return error 400 (Bad Request)
+            Err(e) => assert_eq!(e.status().unwrap(), 400),
         };
 
         self
diff --git a/consensus/merkle_proof/src/lib.rs b/consensus/merkle_proof/src/lib.rs
index 494c73d05ce..9952975e867 100644
--- a/consensus/merkle_proof/src/lib.rs
+++ b/consensus/merkle_proof/src/lib.rs
@@ -1,4 +1,4 @@
-use ethereum_hashing::{ZERO_HASHES, hash, hash32_concat};
+use ethereum_hashing::{ZERO_HASHES, hash32_concat};
 use safe_arith::ArithError;
 use std::sync::LazyLock;
 
@@ -382,20 +382,19 @@ pub fn verify_merkle_proof(
 pub fn merkle_root_from_branch(leaf: H256, branch: &[H256], depth: usize, index: usize) -> H256 {
     assert_eq!(branch.len(), depth, "proof length should equal depth");
 
-    let mut merkle_root = leaf.as_slice().to_vec();
+    let mut merkle_root = leaf.0;
 
-    for (i, leaf) in branch.iter().enumerate().take(depth) {
+    for (i, branch_node) in branch.iter().enumerate().take(depth) {
         let ith_bit = (index >> i) & 0x01;
-        if ith_bit == 1 {
-            merkle_root = hash32_concat(leaf.as_slice(), &merkle_root)[..].to_vec();
+        let (left, right) = if ith_bit == 1 {
+            (branch_node.as_slice(), merkle_root.as_slice())
         } else {
-            let mut input = merkle_root;
-            input.extend_from_slice(leaf.as_slice());
-            merkle_root = hash(&input);
-        }
+            (merkle_root.as_slice(), branch_node.as_slice())
+        };
+        merkle_root = hash32_concat(left, right);
     }
 
-    H256::from_slice(&merkle_root)
+    H256::from(merkle_root)
 }
 
 impl From<ArithError> for MerkleTreeError {