Added a case-sensitivity check to called controller methods, as per this bug report: http://codeigniter.com/bug_tracker/bug/4560/
diff --git a/system/codeigniter/CodeIgniter.php b/system/codeigniter/CodeIgniter.php
index 692d84a..27094d2 100644
--- a/system/codeigniter/CodeIgniter.php
+++ b/system/codeigniter/CodeIgniter.php
@@ -169,11 +169,10 @@
 $class  = $RTR->fetch_class();

 $method = $RTR->fetch_method();

 

-

 if ( ! class_exists($class)

 	OR $method == 'controller'

 	OR strncmp($method, '_', 1) == 0

-	OR in_array($method, get_class_methods('Controller'), TRUE)

+	OR in_array(strtolower($method), array_map('strtolower', get_class_methods('Controller')))

 	)

 {

 	show_404("{$class}/{$method}");