diff --git a/AFNetworking/AFURLConnectionOperation.m b/AFNetworking/AFURLConnectionOperation.m
index 114cec2..5339da2 100644
--- a/AFNetworking/AFURLConnectionOperation.m
+++ b/AFNetworking/AFURLConnectionOperation.m
@@ -375,7 +375,7 @@ didReceiveResponse:(NSURLResponse *)response
     
     if (self.outputStream) {
         if ([self.outputStream hasSpaceAvailable]) {
-            const uint8_t *dataBuffer = [data bytes];
+            const uint8_t *dataBuffer = (uint8_t *) [data bytes];
             [self.outputStream write:&dataBuffer[0] maxLength:[data length]];
         }
     } else {