diff --git a/firmware/tools/generate_world_map.bin.py b/firmware/tools/generate_world_map.bin.py
index ffb28659..38f575e2 100755
--- a/firmware/tools/generate_world_map.bin.py
+++ b/firmware/tools/generate_world_map.bin.py
@@ -36,7 +36,7 @@ outfile.write(struct.pack('H', im.size[1]))
 print("Generating: \t" + outfile.name + "\n from\t\t" + im.filename + "\n please wait...");
 
 for y in range (0, im.size[1]):
-	line = ''
+	line = b''
 	for x in range (0, im.size[0]):
 		# RRRRRGGGGGGBBBBB
 		pixel_lcd = (pix[x, y][0] >> 3) << 11
@@ -47,8 +47,8 @@ for y in range (0, im.size[1]):
 		# pixel_lcd = (pix[x, y][0] >> 5) << 5
 		# pixel_lcd |= (pix[x, y][1] >> 5) << 2
 		# pixel_lcd |= (pix[x, y][2] >> 6)
-		line += str(struct.pack('H', pixel_lcd))
-	outfile.write(line.encode('utf-8'))
+		line += struct.pack('H', pixel_lcd)
+	outfile.write(line)
 	print(str(y) + '/' + str(im.size[1]) + '\r', end="")
 
 print("Ready.");