diff --git a/buildkite/install-python36.sh b/buildkite/install-python36.sh
index 3c7e74a..a11c1b6 100755
--- a/buildkite/install-python36.sh
+++ b/buildkite/install-python36.sh
@@ -31,7 +31,7 @@
 pushd /usr/local/src
 
 curl -O "https://www.python.org/ftp/python/${PYTHON_VERSION}/Python-${PYTHON_VERSION}.tar.xz"
-tar xvfJ "Python-${PYTHON_VERSION}.tar.xz"
+tar xfJ "Python-${PYTHON_VERSION}.tar.xz"
 rm -f "Python-${PYTHON_VERSION}.tar.xz"
 cd "Python-${PYTHON_VERSION}"
 
@@ -43,7 +43,7 @@
 EOF
 
 echo "Compiling Python ${PYTHON_VERSION} ..."
-./configure --enable-ipv6
+./configure --quiet --enable-ipv6
 make -s -j8 all > /dev/null
 echo "Installing Python ${PYTHON_VERSION} ..."
 make -s altinstall > /dev/null
diff --git a/buildkite/setup-windows-manual.ps1 b/buildkite/setup-windows-manual.ps1
index db3d99b..0f1c61c 100755
--- a/buildkite/setup-windows-manual.ps1
+++ b/buildkite/setup-windows-manual.ps1
@@ -234,7 +234,7 @@
 
 ## Download and install the Buildkite agent.
 Write-Host "Downloading Buildkite agent..."
-$buildkite_agent_version = "3.0-beta.39"
+$buildkite_agent_version = "3.0-beta.40"
 $buildkite_agent_url = "https://github.com/buildkite/agent/releases/download/v${buildkite_agent_version}/buildkite-agent-windows-amd64-${buildkite_agent_version}.zip"
 $buildkite_agent_zip = "c:\temp\buildkite-agent.zip"
 $buildkite_agent_root = "c:\buildkite"
@@ -248,8 +248,11 @@
 [Environment]::SetEnvironmentVariable("PATH", $env:PATH, "Machine")
 
 ## Store the image version in a file.
-(New-Object Net.WebClient).DownloadFile("http://metadata.google.internal/computeMetadata/v1/instance/attributes/image-version", "c:\buildkite\image.version")
-$image_version = Get-Content "c:\buildkite\image.version" -Raw
+$web_client = New-Object Net.WebClient
+$web_client.Headers.add("Metadata-Flavor","Google")
+$image_version = $web_client.DownloadString("http://metadata.google.internal/computeMetadata/v1/instance/attributes/image-version")
+$image_version = $image_version.Trim()
+$image_version | Set-Content -Path "c:\buildkite\image.version"
 
 ## Remove empty folders (";;") from PATH.
 $env:PATH = [Environment]::GetEnvironmentVariable("PATH", "Machine").replace(";;", ";")
diff --git a/buildkite/setup-windows.ps1 b/buildkite/setup-windows.ps1
index dfa42cb..a79c1e9 100755
--- a/buildkite/setup-windows.ps1
+++ b/buildkite/setup-windows.ps1
@@ -233,7 +233,7 @@
 
 ## Download and install the Buildkite agent.
 Write-Host "Downloading Buildkite agent..."
-$buildkite_agent_version = "3.0-beta.39"
+$buildkite_agent_version = "3.0-beta.40"
 $buildkite_agent_url = "https://github.com/buildkite/agent/releases/download/v${buildkite_agent_version}/buildkite-agent-windows-amd64-${buildkite_agent_version}.zip"
 $buildkite_agent_zip = "c:\temp\buildkite-agent.zip"
 $buildkite_agent_root = "c:\buildkite"
@@ -247,8 +247,11 @@
 [Environment]::SetEnvironmentVariable("PATH", $env:PATH, "Machine")
 
 ## Store the image version in a file.
-(New-Object Net.WebClient).DownloadFile("http://metadata.google.internal/computeMetadata/v1/instance/attributes/image-version", "c:\buildkite\image.version")
-$image_version = Get-Content "c:\buildkite\image.version" -Raw
+$web_client = New-Object Net.WebClient
+$web_client.Headers.add("Metadata-Flavor","Google")
+$image_version = $web_client.DownloadString("http://metadata.google.internal/computeMetadata/v1/instance/attributes/image-version")
+$image_version = $image_version.Trim()
+$image_version | Set-Content -Path "c:\buildkite\image.version"
 
 ## Remove empty folders (";;") from PATH.
 $env:PATH = [Environment]::GetEnvironmentVariable("PATH", "Machine").replace(";;", ";")