diff --git a/test/tools/yulInterpreter/EVMInstructionInterpreter.cpp b/test/tools/yulInterpreter/EVMInstructionInterpreter.cpp
index cec5d5501346..aa93c682414d 100644
--- a/test/tools/yulInterpreter/EVMInstructionInterpreter.cpp
+++ b/test/tools/yulInterpreter/EVMInstructionInterpreter.cpp
@@ -565,6 +565,26 @@ u256 EVMInstructionInterpreter::evalBuiltin(
 		return 0;
 	}
 
+	if (fun == "loadimmutable")
+	{
+		yulAssert(_arguments.size() == 1);
+		yulAssert(std::holds_alternative<Literal>(_arguments[0]));
+		std::string const identifier = formatLiteral(std::get<Literal>(_arguments[0]));
+		// Return a deterministic value based on the identifier.
+		// This is sufficient for differential fuzzing since the same identifier
+		// will always return the same value, maintaining trace equivalence.
+		return u256(h256(identifier));
+	}
+
+	if (fun == "setimmutable")
+	{
+		yulAssert(_arguments.size() == 3);
+		// No-op: The real implementation patches placeholder bytes in memory-loaded runtime code.
+		// For differential fuzzing, this ensures correct code never fails (no false positives), though some
+		// bugs in setimmutable handling may not be detected (potential false negatives).
+		return 0;
+	}
+
 	yulAssert(false, "Unknown builtin: " + fun);
 }