diff --git a/tools/build_protobuf b/tools/build_protobuf
index e46db4c559..8a30407ed6 100755
--- a/tools/build_protobuf
+++ b/tools/build_protobuf
@@ -1,24 +1,31 @@
 #!/bin/bash
-CURDIR=$(pwd)
-mkdir -p $CURDIR/pb2/
+set -e
 
-mkdir -p ../trezorlib/messages
+cd "$(dirname "$0")"
 
-INDEX=../trezorlib/messages/__init__.py
-rm -f $INDEX
-echo '# Automatically generated by pb2py' >> $INDEX
-echo '' >> $INDEX
+GENPATH="../trezorlib/messages"
+INDEX="$GENPATH/__init__.py"
+PROTO_PATH="../../trezor-common/protob"
+PROTO_FILES=(types messages storage)
+PB2_OUT="pb2"
 
-for i in types messages storage ; do
+mkdir -p "$GENPATH"
+
+cat > "$INDEX" << EOF
+# Automatically generated by pb2py
+
+EOF
+
+mkdir -p "$PB2_OUT"
+
+for file in "${PROTO_FILES[@]}"; do
     # Compile .proto files to python2 modules using google protobuf library
-    cd $CURDIR/../../trezor-common/protob
-    protoc --python_out=$CURDIR/pb2/ -I/usr/include -I. $i.proto
+    protoc --python_out="$PB2_OUT" -I"$PROTO_PATH" "$file.proto"
 done
 
-for i in types messages storage ; do
+for file in "${PROTO_FILES[@]}"; do
     # Convert google protobuf library to trezor's internal format
-    cd $CURDIR
-    ./pb2py -P "trezorlib.protobuf" -p $CURDIR/pb2 -l $INDEX $i ../trezorlib/messages/
+    ./pb2py -P "trezorlib.protobuf" -p "$PB2_OUT" -l "$INDEX" "$file" "$GENPATH"
 done
 
-rm -rf $CURDIR/pb2/
+rm -rf "$PB2_OUT"