diff --git a/Dockerfile.chameleon b/Dockerfile.chameleon
index ea3e53a..fdf8c8c 100644
--- a/Dockerfile.chameleon
+++ b/Dockerfile.chameleon
@@ -23,7 +23,8 @@
 
 # Install protoc version 3.0.0; this is not yet the supported
 # version on xenial, so we need to "backport" it
-RUN apt-get install -y zlib1g-dev wget && \
+RUN apt-get update && \
+    apt-get install -y zlib1g-dev wget && \
     wget http://ftp.us.debian.org/debian/pool/main/p/protobuf/libprotoc10_3.0.0-7_amd64.deb && \
     wget http://ftp.us.debian.org/debian/pool/main/p/protobuf/libprotobuf-lite10_3.0.0-7_amd64.deb && \
     wget http://ftp.us.debian.org/debian/pool/main/p/protobuf/libprotobuf-dev_3.0.0-7_amd64.deb && \