diff --git a/passes/techmap/abc.cc b/passes/techmap/abc.cc
index 0c2576c1a..dfaee9415 100644
--- a/passes/techmap/abc.cc
+++ b/passes/techmap/abc.cc
@@ -291,12 +291,15 @@ void AbcModuleState::extract_cell(RTLIL::Module *module, RTLIL::Cell *cell, bool
 				return;
 		}
 
-		if (keepff)
-			for (auto &c : ff.sig_q.chunks())
-				if (c.wire != nullptr)
-					c.wire->attributes[ID::keep] = 1;
-
-		map_signal(ff.sig_q, type, map_signal(ff.sig_d));
+		int gate_id = map_signal(ff.sig_q, type, map_signal(ff.sig_d));
+		if (keepff) {
+			SigBit bit = ff.sig_q;
+			if (assign_map(bit).wire != nullptr) {
+				signal_list[gate_id].is_port = true;
+			}
+			if (bit.wire != nullptr)
+				bit.wire->attributes[ID::keep] = 1;
+		}
 
 		ff.remove();
 		return;