diff --git a/evm/src/cpu/kernel/asm/core/create.asm b/evm/src/cpu/kernel/asm/core/create.asm
index 5a942854..0bcddecf 100644
--- a/evm/src/cpu/kernel/asm/core/create.asm
+++ b/evm/src/cpu/kernel/asm/core/create.asm
@@ -137,9 +137,11 @@ after_constructor:
     // stack: new_ctx, leftover_gas, success, address, kexit_info
     POP
 
-    // TODO: EIP-3541: Reject new contract code starting with the 0xEF byte
 
     // TODO: Skip blocks below if success is false.
+    // EIP-3541: Reject new contract code starting with the 0xEF byte
+    PUSH 0 %mload_current(@SEGMENT_RETURNDATA) %eq_const(0xEF) %jumpi(fault_exception)
+
     // Charge gas for the code size.
     SWAP3
     // stack: kexit_info, success, address, leftover_gas
diff --git a/evm/src/cpu/kernel/asm/core/process_txn.asm b/evm/src/cpu/kernel/asm/core/process_txn.asm
index 6c466749..3e16bbd4 100644
--- a/evm/src/cpu/kernel/asm/core/process_txn.asm
+++ b/evm/src/cpu/kernel/asm/core/process_txn.asm
@@ -144,6 +144,10 @@ process_contract_creation_txn_after_code_loaded:
 global process_contract_creation_txn_after_constructor:
     // stack: success, leftover_gas, new_ctx, address, retdest
     POP // TODO: Success will go into the receipt when we support that.
+
+    // EIP-3541: Reject new contract code starting with the 0xEF byte
+    PUSH 0 %mload_current(@SEGMENT_RETURNDATA) %eq_const(0xEF) %assert_zero // TODO: need to revert changes here.
+
     // stack: leftover_gas, new_ctx, address, retdest
     %returndatasize // Size of the code.
     // stack: code_size, leftover_gas, new_ctx, address, retdest