diff --git a/OpenCL/m21800-pure.cl b/OpenCL/m21800-pure.cl
index 4706594bd..fc447c94a 100644
--- a/OpenCL/m21800-pure.cl
+++ b/OpenCL/m21800-pure.cl
@@ -513,7 +513,7 @@ KERNEL_FQ void m21800_comp (KERN_ATTR_TMPS_ESALT (electrum_tmp_t, electrum_t))
 
   // early reject
 
-  if (buf[0] & 0x0006ffff != 0x00049c78) return; // allow 0b100 or 0b101 at the end of 3rd byte
+  if ((buf[0] & 0x0006ffff) != 0x00049c78) return; // allow 0b100 or 0b101 at the end of 3rd byte
 
   buf[1] ^= iv[1];
   buf[2] ^= iv[2];