diff --git a/src/Http2/Http2Parser.php b/src/Http2/Http2Parser.php
index fab9e9d..db5cfe6 100644
--- a/src/Http2/Http2Parser.php
+++ b/src/Http2/Http2Parser.php
@@ -408,7 +408,7 @@ private function parseHeaders(string $frameBuffer, int $frameLength, int $frameF
         $padding = $isPadded ? \ord($header[0]) : 0;
 
         if ($isPriority) {
-            ['parent' => $parent, 'weight' => $weight] = \unpack("Nparent/cweight", $header, $isPadded ? 1 : 0);
+            ['parent' => $parent, 'weight' => $weight] = \unpack("Nparent/Cweight", $header, $isPadded ? 1 : 0);
 
             $parent &= 0x7fffffff;
 
@@ -465,7 +465,7 @@ private function parsePriorityFrame(string $frameBuffer, int $frameLength, int $
             $this->throwInvalidFrameSizeError();
         }
 
-        ['parent' => $parent, 'weight' => $weight] = \unpack("Nparent/cweight", $frameBuffer);
+        ['parent' => $parent, 'weight' => $weight] = \unpack("Nparent/Cweight", $frameBuffer);
 
         if ($exclusive = ($parent & 0x80000000)) {
             $parent &= 0x7fffffff;