diff --git a/tests/rpmostree_rebase.pm b/tests/rpmostree_rebase.pm
index 533dd72d..e91d97c9 100644
--- a/tests/rpmostree_rebase.pm
+++ b/tests/rpmostree_rebase.pm
@@ -44,6 +44,7 @@ sub run {
     }
     elsif ($current =~ "silverblue") {
         my $relnum = get_release_number;
+        $rebase = $relnum - 1;
         # on update tests, just rebase to the 'official' ref for the
         # release, as opposed to the custom ref we used when building;
         # this should be more reliable than a different release