Index: uspace/app/trace/ipcp.c
===================================================================
--- uspace/app/trace/ipcp.c	(revision 40fd6f0603f68e631684ecf21999cdf323028976)
+++ uspace/app/trace/ipcp.c	(revision c1694b6b243b360b5f1fbf0629b5e7d4f7f4a515)
@@ -35,4 +35,5 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <str_error.h>
 #include <inttypes.h>
 #include <adt/hash_table.h>
@@ -347,5 +348,5 @@
 {
 	if ((display_mask & DM_SYSTEM) != 0) {
-		printf("Hang phone %d up -> %d\n", phone, rc);
+		printf("Hang phone %d up -> %s\n", phone, str_error_name(rc));
 		ipcp_connection_clear(phone);
 	}
Index: uspace/app/trace/trace.c
===================================================================
--- uspace/app/trace/trace.c	(revision 40fd6f0603f68e631684ecf21999cdf323028976)
+++ uspace/app/trace/trace.c	(revision c1694b6b243b360b5f1fbf0629b5e7d4f7f4a515)
@@ -164,5 +164,5 @@
 	int rc = udebug_begin(ksess);
 	if (rc < 0) {
-		printf("udebug_begin() -> %d\n", rc);
+		printf("udebug_begin() -> %s\n", str_error_name(rc));
 		return rc;
 	}
@@ -170,5 +170,5 @@
 	rc = udebug_set_evmask(ksess, UDEBUG_EM_ALL);
 	if (rc < 0) {
-		printf("udebug_set_evmask(0x%x) -> %d\n ", UDEBUG_EM_ALL, rc);
+		printf("udebug_set_evmask(0x%x) -> %s\n ", UDEBUG_EM_ALL, str_error_name(rc));
 		return rc;
 	}
@@ -188,5 +188,5 @@
 		THBUF_SIZE*sizeof(unsigned), &tb_copied, &tb_needed);
 	if (rc < 0) {
-		printf("udebug_thread_read() -> %d\n", rc);
+		printf("udebug_thread_read() -> %s\n", str_error_name(rc));
 		return rc;
 	}
@@ -605,5 +605,5 @@
 	rc = get_thread_list();
 	if (rc < 0) {
-		printf("Failed to get thread list (error %d)\n", rc);
+		printf("Failed to get thread list (%s)\n", str_error(rc));
 		return;
 	}
@@ -644,5 +644,5 @@
 			rc = udebug_stop(sess, thash);
 			if (rc != EOK)
-				printf("Error: stop -> %d\n", rc);
+				printf("Error: stop -> %s\n", str_error_name(rc));
 			break;
 		case KC_R: