diff --git a/server/Worker.hs b/server/Worker.hs
index 31ddcdc6c936040b0873e0d9c5622e2773fa01f8..a9ffce310e5a906b649d0323825d2ed744392d64 100644
--- a/server/Worker.hs
+++ b/server/Worker.hs
@@ -93,7 +93,7 @@ runJob offline config Job {..} done = do
         True | offline -> logInfoN $ "offline mode: not updating " <> show gitdir
              | otherwise ->
           (liftIO $ callgit gitdir
-            [ "fetch", "origin", toString ref, "--depth", "1" ])
+            [ "fetch", "origin", toString (ref <> ":" <> ref) ])
       rev <- map T.strip -- git returns a newline here
         $ readgit' gitdir ["rev-parse", toString ref]