diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index 927a47bbff0e4997e9b109e30a83a513290f29c1..516fb52993dec8b7457f093f8728af8840e210eb 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -589,11 +589,11 @@ static char *usb_get_fw_dev_path(DeviceState *qdev)
         nr = strtol(in, &in, 10);
         if (in[0] == '.') {
             /* some hub between root port and device */
-            pos += snprintf(fw_path + pos, fw_len - pos, "hub@%ld/", nr);
+            pos += snprintf(fw_path + pos, fw_len - pos, "hub@%lx/", nr);
             in++;
         } else {
             /* the device itself */
-            pos += snprintf(fw_path + pos, fw_len - pos, "%s@%ld",
+            pos += snprintf(fw_path + pos, fw_len - pos, "%s@%lx",
                             qdev_fw_name(qdev), nr);
             break;
         }