diff --git a/src/danog/MadelineProto/API.php b/src/danog/MadelineProto/API.php
index 3f78864e..25535703 100644
--- a/src/danog/MadelineProto/API.php
+++ b/src/danog/MadelineProto/API.php
@@ -30,6 +30,7 @@ class API extends APIFactory
                     clearstatcache();
                 }
                 $lock = fopen($lock, 'r');
+                \danog\MadelineProto\Logger::log(['Waiting for shared lock of serialization lockfile...']);
                 flock($lock, LOCK_SH);
                 $unserialized = file_get_contents($params);
                 flock($lock, LOCK_UN);
diff --git a/src/danog/MadelineProto/Logger.php b/src/danog/MadelineProto/Logger.php
index 54dda793..bc689726 100644
--- a/src/danog/MadelineProto/Logger.php
+++ b/src/danog/MadelineProto/Logger.php
@@ -81,7 +81,7 @@ class Logger
     ];
 
     public static $storage = [];
-    public static $mode = null;
+    public static $mode = 1;
     public static $optional = null;
     public static $constructed = false;
     public static $prefix = '';
@@ -165,7 +165,7 @@ class Logger
             return false;
         }
         if (!self::$constructed) {
-            throw new Exception(\danog\MadelineProto\Lang::$current_lang['constructor_function_uncalled']);
+//            throw new Exception(\danog\MadelineProto\Lang::$current_lang['constructor_function_uncalled']);
         }
         $prefix = self::$prefix;
         if (\danog\MadelineProto\Logger::$has_thread && is_object(\Thread::getCurrentThread())) {
diff --git a/src/danog/MadelineProto/MTProtoTools/Files.php b/src/danog/MadelineProto/MTProtoTools/Files.php
index 78af648c..cb3f37b6 100644
--- a/src/danog/MadelineProto/MTProtoTools/Files.php
+++ b/src/danog/MadelineProto/MTProtoTools/Files.php
@@ -240,11 +240,15 @@ trait Files
         $file = realpath($file);
         $message_media = $this->get_download_info($message_media);
         $stream = fopen($file, 'r+b');
+        \danog\MadelineProto\Logger::log(['Waiting for lock of file to download...']);
         flock($stream, LOCK_EX);
-        $this->download_to_stream($message_media, $stream, $cb, filesize($file), -1);
-        flock($stream, LOCK_UN);
-        fclose($stream);
-        clearstatcache();
+        try {
+            $this->download_to_stream($message_media, $stream, $cb, filesize($file), -1);
+        } finally {
+            flock($stream, LOCK_UN);
+            fclose($stream);
+            clearstatcache();
+        }
 
         return $file;
     }
@@ -265,7 +269,7 @@ trait Files
             $end = $message_media['size'];
         }
         $size = $end - $offset;
-        $part_size = 128 * 1024;
+        $part_size = 1024 * 1024;
         $percent = 0;
         $datacenter = isset($message_media['InputFileLocation']['dc_id']) ? $message_media['InputFileLocation']['dc_id'] : $this->datacenter->curdc;
         if (isset($message_media['key'])) {
@@ -290,9 +294,6 @@ trait Files
                 $res = $cdn ? $this->method_call('upload.getCdnFile', ['file_token' => $message_media['file_token'], 'offset' => $offset, 'limit' => $part_size], ['heavy' => true, 'datacenter' => $datacenter]) : $this->method_call('upload.getFile', ['location' => $message_media['InputFileLocation'], 'offset' => $offset, 'limit' => $part_size], ['heavy' => true, 'datacenter' => &$datacenter]);
             } catch (\danog\MadelineProto\RPCErrorException $e) {
                 switch ($e->rpc) {
-                    case 'OFFSET_INVALID':
-                    //\Rollbar\Rollbar::log(\Rollbar\Payload\Level::error(), $e->rpc, ['info' => $message_media, 'offset' => $offset]);
-                    break;
                     case 'FILE_TOKEN_INVALID':
                     $cdn = false;
                     continue 2;
diff --git a/src/danog/MadelineProto/Serialization.php b/src/danog/MadelineProto/Serialization.php
index c6e2a60b..463107c3 100644
--- a/src/danog/MadelineProto/Serialization.php
+++ b/src/danog/MadelineProto/Serialization.php
@@ -52,11 +52,15 @@ class Serialization
             clearstatcache();
         }
         $lock = fopen($lock, 'w');
+        \danog\MadelineProto\Logger::log(['Waiting for exclusive lock of serialization lockfile...']);
         flock($lock, LOCK_EX);
-        $wrote = file_put_contents($filename.'.temp.session', serialize($instance));
-        rename($filename.'.temp.session', $filename);
-        flock($lock, LOCK_UN);
-        fclose($lock);
+        try {
+            $wrote = file_put_contents($filename.'.temp.session', serialize($instance));
+            rename($filename.'.temp.session', $filename);
+        } finally {
+            flock($lock, LOCK_UN);
+            fclose($lock);
+        }
 
         return $wrote;
     }
@@ -78,6 +82,8 @@ class Serialization
                 clearstatcache();
             }
             $lock = fopen($lock, 'r');
+
+            \danog\MadelineProto\Logger::log(['Waiting for shared lock of serialization lockfile...']);
             flock($lock, LOCK_SH);
             $unserialized = file_get_contents($filename);
             flock($lock, LOCK_UN);