diff --git a/scripts/stm32_mem.py b/scripts/stm32_mem.py
index 51a8537..1867488 100755
--- a/scripts/stm32_mem.py
+++ b/scripts/stm32_mem.py
@@ -72,7 +72,7 @@ def stm32_read(dev):
 	return data
 
 def stm32_manifest(dev):
-	dev.download(0, "")
+	dev.download(0, b"")
 	while True:
 		try:
 			status = dev.get_status()