diff --git a/Dockerfile b/Dockerfile
index 08213ec..ecca657 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,11 +2,8 @@
 
 FROM debian:9
 
-# update repositories
-
-RUN apt-get update
-
 # install build tools and dependencies
 
-RUN apt-get install -y build-essential git python python-ecdsa gcc-arm-none-eabi
-RUN apt-get install -y protobuf-compiler libprotobuf-dev python-protobuf
+RUN apt-get update && apt-get install -y \
+    build-essential git python python-ecdsa gcc-arm-none-eabi \
+    protobuf-compiler libprotobuf-dev python-protobuf