--- build/moz.configure/toolchain.configure.orig
+++ build/moz.configure/toolchain.configure
@@ -113,7 +113,7 @@
         if bootstrapped:
             sdk = [bootstrapped]
         if sdk:
-            sdk = sdk[0]
+            return sdk[0]
             try:
                 version = get_sdk_version(sdk)
             except Exception as e: