The Broadcoms UBI parser requires the binary sequence number to be exactly three bytes.

brcm_fw_tool/image-ubi.c

@@ -688,7 +688,7 @@ static int meta_generate_blob(const char *tmpPath, int seqNo)
 	if(!res) res = meta_generate_record(outFd, ubiStr1, data, strlen(data));
 
 	// The sequence value.
-	snprintf(data, sizeof(data), "%d", seqNo);
+	snprintf(data, sizeof(data), "%3.3d", seqNo);
 	if(!res) res = meta_generate_record(outFd, ubiStr2, data, strlen(data));
 
 	// Ending null trailer.