diff --git a/bootstrap.sh b/bootstrap.sh
index 4e05477..cb1a181 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -1,9 +1,20 @@
 #!/bin/bash
 trap 'exit' ERR
 
+function getGnHash()
+{
+  local OS_NAME=$1
+  local FILE_EXT=
+  if [ "$OS_NAME" == "win" ]; then
+    eval FILE_EXT=.exe
+  fi
+  local hash=`curl https://chromium.googlesource.com/chromium/buildtools/+/master/$OS_NAME/gn$FILE_EXT.sha1 | grep -Po '<td class="FileContents-lineContents" id="1"><span class="pln">\K[A-Za-z0-9]+'`
+  echo $hash
+}
+
 if [ ! -f gsutil/gsutil ]
   then
-    rm gsutil.tar.gz
+    rm -fr gsutil.tar.gz
     wget https://commondatastorage.googleapis.com/pub/gsutil.tar.gz
     tar zxf gsutil.tar.gz
     gsutil/gsutil --version
@@ -14,11 +25,14 @@ mkdir -p linux
 mkdir -p win
 
 # https://chromium.googlesource.com/chromium/buildtools/+/master/win/gn.exe.sha1
-gsutil/gsutil cp gs://chromium-gn/1380b36db64aace2523d6bea32c59e48a51c82a4 win/gn.exe
+echo "win: $(getGnHash win)"
+gsutil/gsutil cp gs://chromium-gn/$(getGnHash win) win/gn.exe
 
 # https://chromium.googlesource.com/chromium/buildtools/+/master/mac/gn.sha1
-gsutil/gsutil cp gs://chromium-gn/a68b194afb05d6a6357cf2e2464136ed7723c305 mac/gn
+echo "mac: $(getGnHash mac)"
+gsutil/gsutil cp gs://chromium-gn/$(getGnHash mac) mac/gn
 
 # https://chromium.googlesource.com/chromium/buildtools/+/master/linux64/gn.sha1 
-gsutil/gsutil cp gs://chromium-gn/4e3a214794b25c37e57b8c690c0b24daa631a420 linux/gn
+echo "linux64: $(getGnHash linux64)"
+gsutil/gsutil cp gs://chromium-gn/$(getGnHash linux64) linux/gn