diff --git a/flac_codec_registration.src.html b/flac_codec_registration.src.html
index eb2c3176..4e38fafd 100644
--- a/flac_codec_registration.src.html
+++ b/flac_codec_registration.src.html
@@ -112,8 +112,8 @@
 </pre>
 
 To check if an {{FlacEncoderConfig}} is valid, run these steps:
-1. If {{FlacEncoderConfig/blockSize}} is not a valid block size,
-    which is described section 5.1 of [[FLAC]], return `false`.
+1. If {{FlacEncoderConfig/blockSize}} is not `0` and is not a valid block size
+    as described in section 5.1 of [[FLAC]], return `false`.
 1. If {{FlacEncoderConfig/compressLevel}} is specified and not within the range of
     `0` (fastest, least compression) and `8` (slowest, most compression) inclusively, return `false`.
 2. Return `true`.