diff --git a/src/kernel_evm/ethereum/src/block.rs b/src/kernel_evm/ethereum/src/block.rs
index 0c2bc94937537383cfcf51b915aedfbc6ee8e49d..d8f57c9dfd9e8b30a2b77b0ec6106abd0e8a6833 100644
--- a/src/kernel_evm/ethereum/src/block.rs
+++ b/src/kernel_evm/ethereum/src/block.rs
@@ -5,8 +5,8 @@
 
 use crate::eth_gen::OwnedHash;
 use crate::rlp_helpers::{
-    decode_field, decode_field_h256, decode_field_u256_le, decode_transaction_hash_list,
-    next,
+    append_u256_le, decode_field, decode_field_h256, decode_field_u256_le,
+    decode_transaction_hash_list, next,
 };
 use crate::transaction::TransactionHash;
 use primitive_types::{H160, H256, U256};
@@ -152,7 +152,7 @@ impl Default for L2Block {
 impl Encodable for L2Block {
     fn rlp_append(&self, s: &mut RlpStream) {
         s.begin_list(6);
-        s.append(&self.number);
+        append_u256_le(s, self.number);
         s.append(&self.hash);
         s.append(&self.parent_hash);
         let transactions_bytes: Vec<Vec<u8>> =
diff --git a/tezt/tests/evm_rollup.ml b/tezt/tests/evm_rollup.ml
index d371a818d20cbb4a6a51077bd59f0c724fc0ae5d..c8b598851a303a14cc7b6e4baff03aaf7397d909 100644
--- a/tezt/tests/evm_rollup.ml
+++ b/tezt/tests/evm_rollup.ml
@@ -2461,15 +2461,13 @@ let test_block_storage_before_and_after_migration =
     ~tags:["evm"; "migration"; "block"; "storage"]
     ~title:"Block storage before and after migration"
   @@ fun protocol ->
+  let block_id = "1" in
   let scenario_prior ~evm_setup:{endpoint; _} =
-    let* (block : Block.t) = Eth_cli.get_block ~block_id:"0" ~endpoint in
+    let* (block : Block.t) = Eth_cli.get_block ~block_id ~endpoint in
     return block
   in
-  let scenario_after ~evm_setup:{endpoint; sc_rollup_node; node; client; _}
-      ~(sanity_check : Block.t) =
-    (* We need to wait for one more block for migration to take place *)
-    let* _level = next_evm_level ~sc_rollup_node ~node ~client in
-    let* (block : Block.t) = Eth_cli.get_block ~block_id:"0" ~endpoint in
+  let scenario_after ~evm_setup:{endpoint; _} ~(sanity_check : Block.t) =
+    let* (block : Block.t) = Eth_cli.get_block ~block_id ~endpoint in
     (* Compare fields stored before migration *)
     assert (block.number = sanity_check.number) ;
     assert (block.hash = sanity_check.hash) ;