From 9d039c55fbf1306a1426a6f9eb875e805d11609c Mon Sep 17 00:00:00 2001
From: Rodi-Can Bozman <rodi.bozman@functori.com>
Date: Fri, 5 Dec 2025 17:01:35 +0100
Subject: [PATCH] Etherlink/IC: store header to allow apply blueprint to take
 over assemble block

---
 etherlink/kernel_latest/kernel/src/sub_block.rs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/etherlink/kernel_latest/kernel/src/sub_block.rs b/etherlink/kernel_latest/kernel/src/sub_block.rs
index a05c687e0f60..13d72e7b5b07 100644
--- a/etherlink/kernel_latest/kernel/src/sub_block.rs
+++ b/etherlink/kernel_latest/kernel/src/sub_block.rs
@@ -6,7 +6,7 @@
 use crate::{
     apply::{pure_fa_deposit, revm_run_transaction},
     block::GAS_LIMIT,
-    block_storage,
+    block_storage, blueprint_storage,
     bridge::{execute_etherlink_deposit, DepositResult},
     chains::{ChainConfigTrait, EvmChainConfig, ETHERLINK_SAFE_STORAGE_ROOT_PATH},
     configuration::fetch_pure_evm_config,
@@ -671,6 +671,13 @@ pub fn assemble_block<Host: Runtime>(
         base_fee_per_gas,
     );
 
+    // We need to store the block header in order for the evm node
+    // to be able to switch between [assemble_block] and [apply_blueprint].
+    // If we don't do the following store instruction, the [apply_blueprint]
+    // will fail to fetch the current block number.
+    let header: blueprint_storage::BlockHeader<_> = sub_block.clone().into();
+    blueprint_storage::store_current_block_header(host, &header)?;
+
     block_storage::store_current(
         host,
         &ETHERLINK_SAFE_STORAGE_ROOT_PATH,
-- 
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