diff --git a/passes/sat/sim.cc b/passes/sat/sim.cc
index 754fbdf95..86736eeb4 100644
--- a/passes/sat/sim.cc
+++ b/passes/sat/sim.cc
@@ -153,6 +153,7 @@ struct SimInstance
 	dict<Cell*, ff_state_t> ff_database;
 	dict<IdString, mem_state_t> mem_database;
 	pool<Cell*> formal_database;
+	pool<Cell*> initstate_database;
 	dict<Cell*, IdString> mem_cells;
 
 	std::vector<Mem> memories;
@@ -256,6 +257,8 @@ struct SimInstance
 			if (cell->type.in(ID($assert), ID($cover), ID($assume))) {
 				formal_database.insert(cell);
 			}
+			if (cell->type == ID($initstate))
+				initstate_database.insert(cell);
 		}
 
 		if (shared->zinit)
@@ -708,6 +711,14 @@ struct SimInstance
 			it.second->update_ph3();
 	}
 
+	void set_initstate_outputs(State state)
+	{
+		for (auto cell : initstate_database)
+			set_state(cell->getPort(ID::Y), state);
+		for (auto child : children)
+			child.second->set_initstate_outputs(state);
+	}
+
 	void writeback(pool<Module*> &wbmods)
 	{
 		if (!ff_database.empty() || !mem_database.empty()) {