diff --git a/Formula/boost.rb b/Formula/boost.rb
index 081129319cc..a7392cb5066 100644
--- a/Formula/boost.rb
+++ b/Formula/boost.rb
@@ -56,7 +56,7 @@ class Boost < Formula
             "threading=multi",
             "install"]
 
-    args << "address-model=32_64" << "pch=off" if ARGV.include? "--universal"
+    args << "address-model=32_64" << "architecture=x86" << "pch=off" if ARGV.include? "--universal"
 
     # we specify libdir too because the script is apparently broken
     system "./bootstrap.sh", "--prefix=#{prefix}", "--libdir=#{lib}"