Index: uspace/lib/device/src/bd_srv.c
===================================================================
--- uspace/lib/device/src/bd_srv.c	(revision edeee9ff19d63d97e85f6ecbd93e661f2b5ff66d)
+++ uspace/lib/device/src/bd_srv.c	(revision 46a47c0ecde5eec9824d8b22b70d9238a2b3a58e)
@@ -1,4 +1,4 @@
 /*
- * Copyright (c) 2012 Jiri Svoboda
+ * Copyright (c) 2023 Jiri Svoboda
  * All rights reserved.
  *
@@ -56,4 +56,5 @@
 	ipc_call_t rcall;
 	if (!async_data_read_receive(&rcall, &size)) {
+		async_answer_0(&rcall, EINVAL);
 		async_answer_0(call, EINVAL);
 		return;
@@ -99,4 +100,5 @@
 	ipc_call_t rcall;
 	if (!async_data_read_receive(&rcall, &size)) {
+		async_answer_0(&rcall, EINVAL);
 		async_answer_0(call, EINVAL);
 		return;
Index: uspace/lib/device/src/io/chardev_srv.c
===================================================================
--- uspace/lib/device/src/io/chardev_srv.c	(revision edeee9ff19d63d97e85f6ecbd93e661f2b5ff66d)
+++ uspace/lib/device/src/io/chardev_srv.c	(revision 46a47c0ecde5eec9824d8b22b70d9238a2b3a58e)
@@ -1,4 +1,4 @@
 /*
- * Copyright (c) 2014 Jiri Svoboda
+ * Copyright (c) 2023 Jiri Svoboda
  * All rights reserved.
  *
@@ -55,4 +55,5 @@
 	ipc_call_t call;
 	if (!async_data_read_receive(&call, &size)) {
+		async_answer_0(&call, EINVAL);
 		async_answer_0(icall, EINVAL);
 		return;