Index: tools/mkfat.py
===================================================================
--- tools/mkfat.py	(revision dbf1be5be4d7ced56dbc0ea7ab6a77eb022a09fa)
+++ tools/mkfat.py	(revision 4d2a4cdff53f384abc37f1db12ad28db9e995051)
@@ -1,3 +1,3 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # Copyright (c) 2008 Martin Decky
@@ -193,6 +193,6 @@
 
 	for char in name.encode('ascii', 'replace').upper():
-		if char in lchars:
-			filtered_name += char
+		if chr(char) in lchars:
+			filtered_name += str.encode(chr(char))
 		else:
 			filtered_name += b'_'