Index: uspace/lib/nic/include/nic_addr_db.h
===================================================================
--- uspace/lib/nic/include/nic_addr_db.h	(revision 25a179efc4ecca45aa90793992b6c1c2743fd07f)
+++ uspace/lib/nic/include/nic_addr_db.h	(revision d5c1051faf4391647834d99babdd4a44ee5d9700)
@@ -60,5 +60,5 @@
 extern int nic_addr_db_insert(nic_addr_db_t *db, const uint8_t *addr);
 extern int nic_addr_db_remove(nic_addr_db_t *db, const uint8_t *addr);
-extern int nic_addr_db_contains(const nic_addr_db_t *db, const uint8_t *addr);
+extern bool nic_addr_db_contains(const nic_addr_db_t *db, const uint8_t *addr);
 extern void nic_addr_db_foreach(const nic_addr_db_t *db,
 	void (*func)(const uint8_t *, void *), void *arg);
Index: uspace/lib/nic/include/nic_rx_control.h
===================================================================
--- uspace/lib/nic/include/nic_rx_control.h	(revision 25a179efc4ecca45aa90793992b6c1c2743fd07f)
+++ uspace/lib/nic/include/nic_rx_control.h	(revision d5c1051faf4391647834d99babdd4a44ee5d9700)
@@ -118,5 +118,5 @@
 extern int nic_rxc_set_addr(nic_rxc_t *rxc,
 	const nic_address_t *prev_addr, const nic_address_t *curr_addr);
-extern int nic_rxc_check(const nic_rxc_t *rxc,
+extern bool nic_rxc_check(const nic_rxc_t *rxc,
 	const void *data, size_t size, nic_frame_type_t *frame_type);
 extern void nic_rxc_hw_filtering(nic_rxc_t *rxc,
Index: uspace/lib/nic/src/nic_addr_db.c
===================================================================
--- uspace/lib/nic/src/nic_addr_db.c	(revision 25a179efc4ecca45aa90793992b6c1c2743fd07f)
+++ uspace/lib/nic/src/nic_addr_db.c	(revision d5c1051faf4391647834d99babdd4a44ee5d9700)
@@ -223,5 +223,5 @@
  * @return true if the address is in the db, false otherwise
  */
-int nic_addr_db_contains(const nic_addr_db_t *db, const uint8_t *addr)
+bool nic_addr_db_contains(const nic_addr_db_t *db, const uint8_t *addr)
 {
 	assert(db && addr);
Index: uspace/lib/nic/src/nic_driver.c
===================================================================
--- uspace/lib/nic/src/nic_driver.c	(revision 25a179efc4ecca45aa90793992b6c1c2743fd07f)
+++ uspace/lib/nic/src/nic_driver.c	(revision d5c1051faf4391647834d99babdd4a44ee5d9700)
@@ -521,5 +521,5 @@
 	fibril_rwlock_read_lock(&nic_data->rxc_lock);
 	nic_frame_type_t frame_type;
-	int check = nic_rxc_check(&nic_data->rx_control, frame->data,
+	bool check = nic_rxc_check(&nic_data->rx_control, frame->data,
 	    frame->size, &frame_type);
 	fibril_rwlock_read_unlock(&nic_data->rxc_lock);
@@ -1092,5 +1092,5 @@
 		fibril_rwlock_read_unlock(&nic->main_lock);
 	}
-	return 0;
+	return EOK;
 }
 
Index: uspace/lib/nic/src/nic_rx_control.c
===================================================================
--- uspace/lib/nic/src/nic_rx_control.c	(revision 25a179efc4ecca45aa90793992b6c1c2743fd07f)
+++ uspace/lib/nic/src/nic_rx_control.c	(revision d5c1051faf4391647834d99babdd4a44ee5d9700)
@@ -394,5 +394,5 @@
  * @return True if the frame passes, false if it does not
  */
-int nic_rxc_check(const nic_rxc_t *rxc, const void *data, size_t size,
+bool nic_rxc_check(const nic_rxc_t *rxc, const void *data, size_t size,
 	nic_frame_type_t *frame_type)
 {