diff --git a/src/drivers/device/cdev.cpp b/src/drivers/device/cdev.cpp
index b157b3f181..6e2ebb1f7b 100644
--- a/src/drivers/device/cdev.cpp
+++ b/src/drivers/device/cdev.cpp
@@ -124,7 +124,7 @@ CDev::register_class_devname(const char *class_devname)
 			if (ret == OK) break;
 		} else {
 			char name[32];
-			snprintf(name, sizeof(name), "%s%u", class_devname, class_instance);
+			snprintf(name, sizeof(name), "%s%d", class_devname, class_instance);
 			ret = register_driver(name, &fops, 0666, (void *)this);
 			if (ret == OK) break;
 		}