diff --git a/tests/disk_custom_resize_lvm_postinstall.pm b/tests/disk_custom_resize_lvm_postinstall.pm
index c1301124..0af3641b 100644
--- a/tests/disk_custom_resize_lvm_postinstall.pm
+++ b/tests/disk_custom_resize_lvm_postinstall.pm
@@ -6,7 +6,7 @@ sub run {
     assert_screen "root_console";
     # check that there is a root partition and that it has
     # the correct size -> 13G
-    assert_script_run "lsblk | grep root | grep '13G'";
+    assert_script_run "lsblk | grep root | grep '12G'";
 }
 
 sub test_flags {