diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 5ae1632edb50fc5ad99fd173d40a1a88523830f5..7d5fab17f03ea033ac41999a180a35303177a266 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -76,7 +76,7 @@ stages:
     # The repo tool seems to insist on having a branch checked out or
     # something like that... Without this we get errors like
     #     fatal: couldn't find remote ref refs/heads/master
-    - git checkout -b master
+    - git checkout -b master && git fetch --unshallow
     # Create/maintain a mirror of all manifest repositories in runner
     # persistent storage, and use that as reference when initializing the
     # build repo, effectively reducing the time spent fetching git repos to