Index: uspace/lib/drv/generic/remote_usb.c
===================================================================
--- uspace/lib/drv/generic/remote_usb.c	(revision 9904eb90403c954baeba44936b6c146c62a3563d)
+++ uspace/lib/drv/generic/remote_usb.c	(revision cfaa35a2627b7c78cd80ef394dfcb862cb582f7b)
@@ -56,5 +56,5 @@
 {
 	if (!exch)
-		return EINVAL;
+		return EBADMEM;
 	sysarg_t addr;
 	const int ret = async_req_1_1(exch, DEV_IFACE_ID(USB_DEV_IFACE),
@@ -65,5 +65,5 @@
 	return ret;
 }
-/*----------------------------------------------------------------------------*/
+
 /** Tell interface number given device can use.
  * @param[in] exch IPC communication exchange
@@ -75,5 +75,5 @@
 {
 	if (!exch)
-		return EINVAL;
+		return EBADMEM;
 	sysarg_t iface_no;
 	const int ret = async_req_1_1(exch, DEV_IFACE_ID(USB_DEV_IFACE),
@@ -83,5 +83,5 @@
 	return ret;
 }
-/*----------------------------------------------------------------------------*/
+
 /** Tell devman handle of device host controller.
  * @param[in] exch IPC communication exchange
@@ -92,5 +92,5 @@
 {
 	if (!exch)
-		return EINVAL;
+		return EBADMEM;
 	devman_handle_t h;
 	const int ret = async_req_1_1(exch, DEV_IFACE_ID(USB_DEV_IFACE),
@@ -121,5 +121,5 @@
 };
 
-/*----------------------------------------------------------------------------*/
+
 void remote_usb_get_my_address(ddf_fun_t *fun, void *iface,
     ipc_callid_t callid, ipc_call_t *call)
@@ -140,5 +140,5 @@
 	}
 }
-/*----------------------------------------------------------------------------*/
+
 void remote_usb_get_my_interface(ddf_fun_t *fun, void *iface,
     ipc_callid_t callid, ipc_call_t *call)
@@ -159,5 +159,5 @@
 	}
 }
-/*----------------------------------------------------------------------------*/
+
 void remote_usb_get_hc_handle(ddf_fun_t *fun, void *iface,
     ipc_callid_t callid, ipc_call_t *call)
Index: uspace/lib/drv/generic/remote_usbhc.c
===================================================================
--- uspace/lib/drv/generic/remote_usbhc.c	(revision 9904eb90403c954baeba44936b6c146c62a3563d)
+++ uspace/lib/drv/generic/remote_usbhc.c	(revision cfaa35a2627b7c78cd80ef394dfcb862cb582f7b)
@@ -165,5 +165,5 @@
 {
 	if (!exch || !address)
-		return EINVAL;
+		return EBADMEM;
 	sysarg_t new_address;
 	const int ret = async_req_4_1(exch, DEV_IFACE_ID(USBHC_DEV_IFACE),
@@ -173,19 +173,19 @@
 	return ret;
 }
-/*----------------------------------------------------------------------------*/
+
 int usbhc_bind_address(async_exch_t *exch, usb_address_t address,
     devman_handle_t handle)
 {
 	if (!exch)
-		return EINVAL;
+		return EBADMEM;
 	return async_req_3_0(exch, DEV_IFACE_ID(USBHC_DEV_IFACE),
 	    IPC_M_USBHC_BIND_ADDRESS, address, handle);
 }
-/*----------------------------------------------------------------------------*/
+
 int usbhc_get_handle(async_exch_t *exch, usb_address_t address,
     devman_handle_t *handle)
 {
 	if (!exch)
-		return EINVAL;
+		return EBADMEM;
 	sysarg_t h;
 	const int ret = async_req_2_1(exch, DEV_IFACE_ID(USBHC_DEV_IFACE),
@@ -195,13 +195,13 @@
 	return ret;
 }
-/*----------------------------------------------------------------------------*/
+
 int usbhc_release_address(async_exch_t *exch, usb_address_t address)
 {
 	if (!exch)
-		return EINVAL;
+		return EBADMEM;
 	return async_req_2_0(exch, DEV_IFACE_ID(USBHC_DEV_IFACE),
 	    IPC_M_USBHC_RELEASE_ADDRESS, address);
 }
-/*----------------------------------------------------------------------------*/
+
 int usbhc_register_endpoint(async_exch_t *exch, usb_address_t address,
     usb_endpoint_t endpoint, usb_transfer_type_t type,
@@ -209,5 +209,5 @@
 {
 	if (!exch)
-		return EINVAL;
+		return EBADMEM;
 	const usb_target_t target =
 	    {{ .address = address, .endpoint = endpoint }};
@@ -220,23 +220,24 @@
 #undef _PACK2
 }
-/*----------------------------------------------------------------------------*/
+
 int usbhc_unregister_endpoint(async_exch_t *exch, usb_address_t address,
     usb_endpoint_t endpoint, usb_direction_t direction)
 {
 	if (!exch)
-		return EINVAL;
+		return EBADMEM;
 	return async_req_4_0(exch, DEV_IFACE_ID(USBHC_DEV_IFACE),
 	    IPC_M_USBHC_UNREGISTER_ENDPOINT, address, endpoint, direction);
 }
-/*----------------------------------------------------------------------------*/
+
 int usbhc_read(async_exch_t *exch, usb_address_t address,
     usb_endpoint_t endpoint, uint64_t setup, void *data, size_t size,
     size_t *rec_size)
 {
+	if (!exch)
+		return EBADMEM;
+
 	if (size == 0 && setup == 0)
 		return EOK;
 
-	if (!exch)
-		return EINVAL;
 	const usb_target_t target =
 	    {{ .address = address, .endpoint = endpoint }};
@@ -284,13 +285,14 @@
 	return EOK;
 }
-/*----------------------------------------------------------------------------*/
+
 int usbhc_write(async_exch_t *exch, usb_address_t address,
     usb_endpoint_t endpoint, uint64_t setup, const void *data, size_t size)
 {
+	if (!exch)
+		return EBADMEM;
+
 	if (size == 0 && setup == 0)
 		return EOK;
 
-	if (!exch)
-		return EINVAL;
 	const usb_target_t target =
 	    {{ .address = address, .endpoint = endpoint }};
@@ -319,5 +321,5 @@
 	return (int) opening_request_rc;
 }
-/*----------------------------------------------------------------------------*/
+
 
 static void remote_usbhc_request_address(ddf_fun_t *, void *, ipc_callid_t, ipc_call_t *);
@@ -384,5 +386,5 @@
 	return trans;
 }
-/*----------------------------------------------------------------------------*/
+
 void remote_usbhc_request_address(ddf_fun_t *fun, void *iface,
     ipc_callid_t callid, ipc_call_t *call)
@@ -406,5 +408,5 @@
 	}
 }
-/*----------------------------------------------------------------------------*/
+
 void remote_usbhc_bind_address(ddf_fun_t *fun, void *iface,
     ipc_callid_t callid, ipc_call_t *call)
@@ -423,5 +425,5 @@
 	async_answer_0(callid, ret);
 }
-/*----------------------------------------------------------------------------*/
+
 void remote_usbhc_get_handle(ddf_fun_t *fun, void *iface,
     ipc_callid_t callid, ipc_call_t *call)
@@ -444,5 +446,5 @@
 	}
 }
-/*----------------------------------------------------------------------------*/
+
 void remote_usbhc_release_address(ddf_fun_t *fun, void *iface,
     ipc_callid_t callid, ipc_call_t *call)
@@ -460,5 +462,5 @@
 	async_answer_0(callid, ret);
 }
-/*----------------------------------------------------------------------------*/
+
 static void callback_out(ddf_fun_t *fun,
     int outcome, void *arg)
@@ -470,5 +472,5 @@
 	async_transaction_destroy(trans);
 }
-/*----------------------------------------------------------------------------*/
+
 static void callback_in(ddf_fun_t *fun,
     int outcome, size_t actual_size, void *arg)
@@ -494,5 +496,5 @@
 	async_transaction_destroy(trans);
 }
-/*----------------------------------------------------------------------------*/
+
 void remote_usbhc_register_endpoint(ddf_fun_t *fun, void *iface,
     ipc_callid_t callid, ipc_call_t *call)
@@ -594,5 +596,5 @@
 	}
 }
-/*----------------------------------------------------------------------------*/
+
 void remote_usbhc_write(
     ddf_fun_t *fun, void *iface, ipc_callid_t callid, ipc_call_t *call)