diff --git a/lib/worker_multibuild.py b/lib/worker_multibuild.py
index 8b2a724..f51abcd 100644
--- a/lib/worker_multibuild.py
+++ b/lib/worker_multibuild.py
@@ -84,7 +84,7 @@ RUN wget https://github.com/Yelp/dumb-init/releases/download/v1.2.5/dumb-init_1.
 RUN dpkg -i dumb-init_*.deb && rm -f dumb-init_*.deb
 
 # buildbot entrypoint
-RUN wget -O /usr/local/bin/buildbot_entrypoint.sh https://git.bitmessage.org/Bitmessage/buildbot-scripts/raw/branch/master/docker/xenial/entrypoint.sh
+RUN [ -f /usr/local/bin/buildbot_entrypoint.sh ] || wget -O /usr/local/bin/buildbot_entrypoint.sh https://git.bitmessage.org/Bitmessage/buildbot-scripts/raw/branch/master/docker/xenial/entrypoint.sh
 RUN chmod +x /usr/local/bin/buildbot_entrypoint.sh
 
 RUN echo 'buildbot ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers