diff --git a/tests/conformance/testdata/Dockerfile.add b/tests/conformance/testdata/Dockerfile.add
index f78180e46..e8d0160f8 100644
--- a/tests/conformance/testdata/Dockerfile.add
+++ b/tests/conformance/testdata/Dockerfile.add
@@ -1,11 +1,11 @@
-FROM busybox
-ADD https://github.com/openshift/origin/raw/master/README.md README.md
+FROM mirror.gcr.io/busybox
+ADD https://github.com/openshift/origin/raw/main/README.md README.md
 USER 1001
-ADD https://github.com/openshift/origin/raw/master/LICENSE .
-ADD https://github.com/openshift/origin/raw/master/LICENSE A
-ADD https://github.com/openshift/origin/raw/master/LICENSE ./a
+ADD https://github.com/openshift/origin/raw/main/LICENSE .
+ADD https://github.com/openshift/origin/raw/main/LICENSE A
+ADD https://github.com/openshift/origin/raw/main/LICENSE ./a
 USER root
 RUN mkdir ./b
-ADD https://github.com/openshift/origin/raw/master/LICENSE ./b/a
-ADD https://github.com/openshift/origin/raw/master/LICENSE ./b/.
+ADD https://github.com/openshift/origin/raw/main/LICENSE ./b/a
+ADD https://github.com/openshift/origin/raw/main/LICENSE ./b/.
 ADD https://github.com/openshift/ruby-hello-world/archive/master.zip /tmp/