Index: uspace/app/trace/trace.c
===================================================================
--- uspace/app/trace/trace.c	(revision 9a1b20c34d5404b8272209d06c0239aa1a2384da)
+++ uspace/app/trace/trace.c	(revision fb9b0b0531bad96f4f612fbc28c26852439f1adb)
@@ -76,4 +76,12 @@
 	rc = ipc_connect_kbox(task_id);
 	printf("-> %d\n", rc);
+
+	if (rc == ENOTSUP) {
+		printf("You do not have userspace debugging support "
+		    "compiled in the kernel.\n");
+		printf("Compile kernel with 'Support for userspace debuggers' "
+		    "(CONFIG_UDEBUG) enabled.\n");
+	}
+
 	phoneid = rc;
 	if (rc < 0) return rc;