diff --git a/ci/install_protobuf.sh b/ci/install_protobuf.sh
index 9476d45..9b14c31 100755
--- a/ci/install_protobuf.sh
+++ b/ci/install_protobuf.sh
@@ -1,8 +1,6 @@
 #!/usr/bin/env bash
 set -e
 
-PROTOC_VERSION=$(cat "$(dirname "$(dirname "$0")")/PROTOC_VERSION")
-
 check_protoc_version () {
   this_version=$(protoc --version)
   return $([ "libprotoc $PROTOC_VERSION" = "$this_version" ])
@@ -17,6 +15,6 @@ echo "[INFO] Installing protobuf $PROTOC_VERSION to $HOME/protobuf..."
 
 cd "$TMPDIR"
 wget "https://github.com/protocolbuffers/protobuf/releases/download/v$PROTOC_VERSION/protoc-$PROTOC_VERSION-linux-x86_64.zip"
-unzip -d "$HOME/protobuf" "protoc-$PROTOC_VERSION-linux-x86_64.zip"
+unzip -o -d "$HOME/protobuf" "protoc-$PROTOC_VERSION-linux-x86_64.zip"
 
 echo "[SUCCESS] Done."