diff --git a/test/functional/tests/conftest.py b/test/functional/tests/conftest.py
index 34f3711a6..62c1a6ae2 100644
--- a/test/functional/tests/conftest.py
+++ b/test/functional/tests/conftest.py
@@ -268,7 +268,7 @@ def base_prepare(item):
                         Udev.settle()
 
         RamDisk.remove_all()
-        for disk in TestRun.dut.disks:
+        for disk in TestRun.disks.values():
             disk_serial = get_disk_serial_number(disk.path)
             if disk.serial_number and disk.serial_number != disk_serial:
                 raise Exception(