diff --git a/src/generator.ml b/src/generator.ml
index 7b5b9d085..69370214f 100755
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -3561,7 +3561,7 @@ an external journal on the journal with UUID C<uuid>.
 See also C<guestfs_mke2journal_U>.");
 
   ("modprobe", (RErr, [String "modulename"]), 194, [],
-   [InitNone, Always, TestRun [["modprobe"; "ext2"]]],
+   [InitNone, Always, TestRun [["modprobe"; "fat"]]],
    "load a kernel module",
    "\
 This loads a kernel module in the appliance.