diff --git a/detect_host_arch.py b/detect_host_arch.py
index 3e170eebe..b0dc69314 100755
--- a/detect_host_arch.py
+++ b/detect_host_arch.py
@@ -12,7 +12,7 @@ import sys
 
 def HostArch():
   """Returns the host architecture with a predictable string."""
-  host_arch = platform.machine()
+  host_arch = platform.machine().lower()
 
   # Convert machine type to format recognized by gyp.
   if re.match(r'i.86', host_arch) or host_arch == 'i86pc':