--- a/src/newgrf.cpp	Fri Feb 23 20:51:10 2007 +0000
+++ b/src/newgrf.cpp	Fri Feb 23 21:03:57 2007 +0000
@@ -1480,6 +1480,11 @@
 	uint8 numinfo;
 	uint8 index;
 
+	if (len == 1) {
+		grfmsg(8, "Silently ignoring one-byte special sprite 0x00");
+		return;
+	}
+
 	if (!check_length(len, 6, "SafeChangeInfo")) return;
 	buf++;
 	feature  = grf_load_byte(&buf);