adding an extra check to only type cast if its a int/true/false so you can still use fields etc in the queries

lib/Cake/Model/Datasource/DboSource.php

@@ -1836,7 +1836,7 @@ class DboSource extends DataSource {
 
 			if ($quoteValues) {
 				$update .= $this->value($value, $model->getColumnType($field));
-			} elseif ($model->getColumnType($field) == 'boolean') {
+			} elseif ($model->getColumnType($field) == 'boolean' && (is_int($value) || is_bool($value))) {
 				$update .= $this->boolean($value, true);
 			} elseif (!$alias) {
 				$update .= str_replace($quotedAlias . '.', '', str_replace(