diff -up ./src/ChunkedStreamDecoder.php.php8 ./src/ChunkedStreamDecoder.php
--- ./src/ChunkedStreamDecoder.php.php8	2021-04-07 16:01:26.474243377 +0200
+++ ./src/ChunkedStreamDecoder.php	2021-04-07 16:01:46.823149969 +0200
@@ -111,7 +111,7 @@ class ChunkedStreamDecoder extends Event
                 }
             }
             $this->nextChunkIsLength = false;
-            if (dechex(@hexdec($lengthChunk)) !== strtolower($lengthChunk)) {
+            if (dechex((int)@hexdec($lengthChunk)) !== strtolower($lengthChunk)) {
                 $this->emit('error', array(
                     new Exception('Unable to validate "' . $lengthChunk . '" as chunk length header'),
                 ));