diff --git a/configure.py b/configure.py
index 7537e30..cf16ef4 100644
--- a/configure.py
+++ b/configure.py
@@ -302,6 +302,12 @@
 
   Returns:
     boolean value of the variable.
+
+  Raises:
+    UserInputError: if an environment variable is set, but it cannot be
+      interpreted as a boolean indicator, assume that the user has made a
+      scripting error, and will continue to provide invalid input.
+      Raise the error to avoid infinitely looping.
   """
   if not question:
     question = 'Do you wish to build TensorFlow with %s support?' % query_item
@@ -319,6 +325,23 @@
     question += ' [y/N]: '
 
   var = environ_cp.get(var_name)
+  if var is not None:
+    var_content = var.strip().lower()
+    true_strings = ('1', 't', 'true', 'y', 'yes')
+    false_strings = ('0', 'f', 'false', 'n', 'no')
+    if var_content in true_strings:
+      var = True
+    elif var_content in false_strings:
+      var = False
+    else:
+      raise UserInputError(
+          'Environment variable %s must be set as a boolean indicator.\n'
+          'The following are accepted as TRUE : %s.\n'
+          'The following are accepted as FALSE: %s.\n'
+          'Current value is %s.' % (
+              var_name, ', '.join(true_strings), ', '.join(false_strings),
+              var))
+
   while var is None:
     user_input_origin = get_input(question)
     user_input = user_input_origin.strip().lower()
@@ -605,8 +628,9 @@
 
   Raises:
     UserInputError: if a query has been attempted n_ask_attempts times without
-    success, assume that the user has made a scripting error, and will continue
-    to provide invalid input. Raise the error to avoid infinitely looping.
+      success, assume that the user has made a scripting error, and will
+      continue to provide invalid input. Raise the error to avoid infinitely
+      looping.
   """
   default = environ_cp.get(var_name) or var_default
   full_query = '%s [Default is %s]: ' % (
@@ -1101,11 +1125,13 @@
 
 def set_trisycl_include_dir(environ_cp):
   """Set TRISYCL_INCLUDE_DIR."""
+
   ask_trisycl_include_dir = ('Please specify the location of the triSYCL '
                              'include directory. (Use --config=sycl_trisycl '
                              'when building with Bazel) '
                              '[Default is %s]: '
                             ) % (_DEFAULT_TRISYCL_INCLUDE_DIR)
+
   while True:
     trisycl_include_dir = get_from_env_or_user_or_default(
         environ_cp, 'TRISYCL_INCLUDE_DIR', ask_trisycl_include_dir,