diff --git a/core/src/utils.rs b/core/src/utils.rs
index 6e942e497..ea4bebacd 100644
--- a/core/src/utils.rs
+++ b/core/src/utils.rs
@@ -77,8 +77,6 @@ pub fn calc_blob_gas_price(excess_blob_gas: u64) -> u128 {
 
 /// Calculates the [EIP-4844] `data_fee` of the transaction.
 ///
-/// Returns `None` if `Cancun` is not enabled. This is enforced in [`Env::validate_block_env`].
-///
 /// [EIP-4844]: https://eips.ethereum.org/EIPS/eip-4844
 #[inline]
 pub fn calc_max_data_fee(max_fee_per_blob_gas: U256, blob_hashes_len: usize) -> U256 {
@@ -87,8 +85,6 @@ pub fn calc_max_data_fee(max_fee_per_blob_gas: U256, blob_hashes_len: usize) ->
 
 /// Calculates the [EIP-4844] `data_fee` of the transaction.
 ///
-/// Returns `None` if `Cancun` is not enabled. This is enforced in [`Env::validate_block_env`].
-///
 /// [EIP-4844]: https://eips.ethereum.org/EIPS/eip-4844
 #[inline]
 pub fn calc_data_fee(blob_gas_price: u128, blob_hashes_len: usize) -> U256 {
diff --git a/evm-tests/jsontests/src/main.rs b/evm-tests/jsontests/src/main.rs
index 2ffa88e20..c53f02a87 100644
--- a/evm-tests/jsontests/src/main.rs
+++ b/evm-tests/jsontests/src/main.rs
@@ -189,6 +189,7 @@ const SKIPPED_CASES: &[&str] = &[
 	"stTransactionTest/ValueOverflow",
 	"stTransactionTest/ValueOverflowParis",
 	// These tests are passing, but they take a lot of time to execute so can going to skip them.
+	// NOTE: do not remove it to know slowest tests. It's useful for development.
 	// "stTimeConsuming/static_Call50000_sha256",
 	// "vmPerformance/loopMul",
 	// "stTimeConsuming/CALLBlake2f_MaxRounds",