diff --git a/ocaml/xapi/xapi_pool_update.ml b/ocaml/xapi/xapi_pool_update.ml
index daed914ccdf..c7f3b4ebdfb 100644
--- a/ocaml/xapi/xapi_pool_update.ml
+++ b/ocaml/xapi/xapi_pool_update.ml
@@ -291,7 +291,7 @@ let attach_helper ~__context ~uuid ~vdi ~use_localhost_proxy =
             "/dev/" ^ Client.VBD.get_device ~rpc ~session_id ~self:vbd
         )
       in
-      with_api_errors (mount device) mount_point ;
+      with_api_errors (mount ~ty:(Some "iso9660") device) mount_point ;
       debug "pool_update.attach_helper Mounted %s" mount_point
   ) ;
   let ip =
diff --git a/ocaml/xenopsd/xc/xenops_server_xen.ml b/ocaml/xenopsd/xc/xenops_server_xen.ml
index d97ddede77b..7f6ede23895 100644
--- a/ocaml/xenopsd/xc/xenops_server_xen.ml
+++ b/ocaml/xenopsd/xc/xenops_server_xen.ml
@@ -2465,9 +2465,8 @@ module VM = struct
         | true ->
             Unixext.with_file path [Unix.O_RDONLY] 0o600 f_synced
         | false ->
-            with_mounted_dir_ro path @@ fun dir ->
-            let filename = Filename.concat dir "suspend-image" in
-            Unixext.with_file filename [Unix.O_RDONLY] 0o600 f_synced
+            error "%s: can't mount %s" __FUNCTION__ path ;
+            internal_error "can't mount %s (not a file or block dev)" path
       )
 
   let wait_ballooning task vm =