diff --git a/doc/Changelog b/doc/Changelog
index c00a1a29f..43a1b50a4 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -1,6 +1,7 @@
 26 July 2021: Wouter
 	- Merge #512: unbound.service.in: upgrade hardening to latest
 	  standards.
+	- Fix readzone unknown type print for memory resize.
 
 21 July 2021: Wouter
 	- Fix that ldns_zone_new_frm_fp_l counts the line number for an empty
diff --git a/testcode/readzone.c b/testcode/readzone.c
index f0351fc56..94511e577 100644
--- a/testcode/readzone.c
+++ b/testcode/readzone.c
@@ -142,7 +142,12 @@ int main(int argc, char *const *argv)
 				s = -1;
 				break;
 			}
-			(void) sldns_wire2str_rr_buf(rr, rr_len, str, str_len);
+			if (print_in_unknown_type_format)
+				(void) sldns_wire2str_rr_unknown_buf(
+					rr, rr_len, str, str_len);
+			else
+				(void) sldns_wire2str_rr_buf(
+					rr, rr_len, str, str_len);
 		}
 		fprintf(stdout, "%s", str);
 	}