diff --git a/lib/zlib/deflate.js b/lib/zlib/deflate.js
index fe5f7c9..b7a2d3f 100644
--- a/lib/zlib/deflate.js
+++ b/lib/zlib/deflate.js
@@ -1419,7 +1419,7 @@ const deflateResetKeep = (strm) => {
     0  // crc32(0, Z_NULL, 0)
   :
     1; // adler32(0, Z_NULL, 0)
-  s.last_flush = Z_NO_FLUSH;
+  s.last_flush = -2;
   _tr_init(s);
   return Z_OK;
 };