diff --git a/pkg/storaged/block/format-dialog.jsx b/pkg/storaged/block/format-dialog.jsx
index 2d37827dc22b..2c8303a4c427 100644
--- a/pkg/storaged/block/format-dialog.jsx
+++ b/pkg/storaged/block/format-dialog.jsx
@@ -290,7 +290,7 @@ function format_dialog_internal(client, path, start, size, enable_dos_extended,
     let [, old_dir, old_opts] = get_fstab_config(block, true,
                                                  content_block?.IdType == "btrfs"
                                                      ? { pathname: "/", id: 5 }
-                                                     : null);
+                                                     : undefined);
     if (old_opts == undefined)
         old_opts = initial_mount_options(client, block);
 
diff --git a/test/verify/check-storage-btrfs b/test/verify/check-storage-btrfs
index b2096961742e..88b5e0b24330 100755
--- a/test/verify/check-storage-btrfs
+++ b/test/verify/check-storage-btrfs
@@ -109,8 +109,9 @@ class TestStorageBtrfs(storagelib.StorageCase):
         b.wait_visible(self.card_row("Storage", name="nonfstab"))
 
         # Format the btrfs device
-        self.click_dropdown(self.card_row("Storage", name="sda"), "Format")
-        self.dialog_wait_open()
+        # The mount of /run/basement might take some time to be recognized by Cockpit
+        self.dialog_open_with_retry(lambda: self.click_dropdown(self.card_row("Storage", name="sda"), "Format"),
+                                    lambda: "/run/basement" in b.text("#dialog"))
         self.checkTeardownAction(1, "Device", dev_1)
         self.checkTeardownAction(1, "Location", "/run/basement")
         self.checkTeardownAction(1, "Action", "unmount, format")